1
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Yao YT, Xu SY, Chang TR. Atomic scale quantum anomalous hall effect in monolayer graphene/MnBi 2Te 4 heterostructure. Mater Horiz 2024. [PMID: 38691397 DOI: 10.1039/d4mh00165f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
The two-dimensional quantum anomalous Hall (QAH) effect is direct evidence of non-trivial Berry curvature topology in condensed matter physics. Searching for QAH in 2D materials, particularly with simplified fabrication methods, poses a significant challenge in future applications. Despite numerous theoretical works proposed for the QAH effect with C = 2 in graphene, neglecting magnetism sources such as proper substrate effects lacks experimental evidence. In this work, we propose the QAH effect in graphene/MnBi2Te4 (MBT) heterostructure based on density-functional theory (DFT) calculations. The monolayer MBT introduces spin-orbital coupling, Zeeman exchange field, and Kekulé distortion as a substrate effect into graphene, resulting in QAH with C = 1 in the heterostructure. Our effective Hamiltonian further presents a rich phase diagram that has not been studied previously. Our work provides a new and practical way to explore the QAH effect in monolayer graphene and the magnetic topological phases by the flexibility of MBT family materials.
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Affiliation(s)
- Yueh-Ting Yao
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
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2
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Han NT, Dien VK, Chang TR, Lin MF. Optical excitations of graphene-like materials: group III-nitrides. Nanoscale Adv 2023; 5:5077-5093. [PMID: 37705768 PMCID: PMC10496912 DOI: 10.1039/d3na00306j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 08/04/2023] [Indexed: 09/15/2023]
Abstract
By using first-principles calculations, we have studied the electronic and optical characteristics of group III-nitrides, such as BN, AlN, GaN, and InN monolayers. The optimized geometry, quasi-particle energy spectra, charge density distributions, band-decomposed charge densities, and Van Hove singularities in density of states are described in the work using physical and chemical pictures and orbital hybridizations found in B-N, Al-N, Ga-N, and In-N chemical bonds. Moreover, the dielectric functions, energy loss functions, absorption coefficients, and reflectance spectra with electron-hole interactions of optical properties are successfully achieved. More importantly, the close relations between electronic and optical properties are successfully demonstrated. The theoretical framework will be useful to research other graphene-like materials.
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Affiliation(s)
- Nguyen Thi Han
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Vo Khuong Dien
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort) Tainan 70101 Taiwan
- Physics Division, National Center for Theoretical Sciences Taipei 10617 Taiwan
| | - Ming-Fa Lin
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Hierarchical Green-Energy Material (Hi-GEM) Research Center, National Cheng Kung University Taiwan
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3
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Thi Han N, Khuong Dien V, Chang TR, Lin MF. Correction: Theoretical investigations of the electronic and optical properties of a GaGeTe monolayer. RSC Adv 2023; 13:21249. [PMID: 37456553 PMCID: PMC10347668 DOI: 10.1039/d3ra90064a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023] Open
Abstract
[This corrects the article DOI: 10.1039/D3RA03160H.].
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Affiliation(s)
- Nguyen Thi Han
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Vo Khuong Dien
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort) Tainan 70101 Taiwan
- Physics Division, National Center for Theoretical Sciences Taipei 10617 Taiwan
| | - Ming-Fa Lin
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Hierarchical Green-Energy Materials (Hi-GEM) Research Center, National Cheng Kung University Taiwan
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4
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Han NT, Dien VK, Chang TR, Lin MF. Theoretical investigations of the electronic and optical properties of a GaGeTe monolayer. RSC Adv 2023; 13:19464-19476. [PMID: 37383693 PMCID: PMC10294289 DOI: 10.1039/d3ra03160h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/08/2023] [Indexed: 06/30/2023] Open
Abstract
Our study focused on exploring the electronic and optical characteristics of the GaGeTe monolayer using first-principles calculations. Our findings showed that this material has remarkable physical and chemical properties attributed to its unique band structure, van Hove singularities in the density of states (DOS), charge density distributions, and charge density differences. We also observed excitonic effects, multiple optical excitation peaks, and strong plasmon modes in the energy loss functions, absorption coefficients, and reflectance spectra, which contribute to its enriched optical response. Moreover, we were able to establish a close relationship between the orbital hybridizations of the initial and final states with each optical excitation peak. Our results suggest that GaGeTe monolayers hold great potential for various semiconductor applications, especially those involving optics. Furthermore, the theoretical framework we used can be applied to study the electronic and optical properties of other graphene-like semiconductor materials.
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Affiliation(s)
- Nguyen Thi Han
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Vo Khuong Dien
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort) Tainan 70101 Taiwan
- Physics Division, National Center for Theoretical Sciences Taipei 10617 Taiwan
| | - Ming-Fa Lin
- Department of Physics, National Cheng Kung University 1 University Road Tainan 70101 Taiwan
- Hierarchical Green-Energy Material (Hi-GEM) Research Center, National Cheng Kung University Taiwan
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5
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Gao A, Liu YF, Qiu JX, Ghosh B, V Trevisan T, Onishi Y, Hu C, Qian T, Tien HJ, Chen SW, Huang M, Bérubé D, Li H, Tzschaschel C, Dinh T, Sun Z, Ho SC, Lien SW, Singh B, Watanabe K, Taniguchi T, Bell DC, Lin H, Chang TR, Du CR, Bansil A, Fu L, Ni N, Orth PP, Ma Q, Xu SY. Quantum metric nonlinear Hall effect in a topological antiferromagnetic heterostructure. Science 2023:eadf1506. [PMID: 37319246 DOI: 10.1126/science.adf1506] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 06/06/2023] [Indexed: 06/17/2023]
Abstract
Quantum geometry in condensed matter physics has two components: the real part quantum metric and the imaginary part Berry curvature. Whereas the effects of Berry curvature have been observed through phenomena such as the quantum Hall effect in 2D electron gases and the anomalous Hall effect (AHE) in ferromagnets, quantum metric has rarely been explored. Here, we report a nonlinear Hall effect induced by quantum metric dipole by interfacing even-layered MnBi2Te4 with black phosphorus. The quantum metric nonlinear Hall effect switches direction upon reversing the AFM spins and exhibits distinct scaling that is independent of the scattering time. Our results open the door to discovering quantum metric responses predicted theoretically and pave the way for applications that bridge nonlinear electronics with AFM spintronics.
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Affiliation(s)
- Anyuan Gao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Yu-Fei Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Jian-Xiang Qiu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Barun Ghosh
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Thaís V Trevisan
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
- Ames National Laboratory, Ames, IA 50011, USA
| | - Yugo Onishi
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tiema Qian
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Shao-Wen Chen
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Mengqi Huang
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Damien Bérubé
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Houchen Li
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Christian Tzschaschel
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Thao Dinh
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Zhe Sun
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Sheng-Chin Ho
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Shang-Wei Lien
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Bahadur Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - David C Bell
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Center for Nanoscale Systems, Harvard University, Cambridge, MA 02138, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chunhui Rita Du
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Peter P Orth
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
- Ames National Laboratory, Ames, IA 50011, USA
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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6
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Qiu JX, Tzschaschel C, Ahn J, Gao A, Li H, Zhang XY, Ghosh B, Hu C, Wang YX, Liu YF, Bérubé D, Dinh T, Gong Z, Lien SW, Ho SC, Singh B, Watanabe K, Taniguchi T, Bell DC, Lu HZ, Bansil A, Lin H, Chang TR, Zhou BB, Ma Q, Vishwanath A, Ni N, Xu SY. Axion optical induction of antiferromagnetic order. Nat Mater 2023; 22:583-590. [PMID: 36894774 DOI: 10.1038/s41563-023-01493-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/25/2023] [Indexed: 05/05/2023]
Abstract
Using circularly polarized light to control quantum matter is a highly intriguing topic in physics, chemistry and biology. Previous studies have demonstrated helicity-dependent optical control of chirality and magnetization, with important implications in asymmetric synthesis in chemistry; homochirality in biomolecules; and ferromagnetic spintronics. We report the surprising observation of helicity-dependent optical control of fully compensated antiferromagnetic order in two-dimensional even-layered MnBi2Te4, a topological axion insulator with neither chirality nor magnetization. To understand this control, we study an antiferromagnetic circular dichroism, which appears only in reflection but is absent in transmission. We show that the optical control and circular dichroism both arise from the optical axion electrodynamics. Our axion induction provides the possibility to optically control a family of [Formula: see text]-symmetric antiferromagnets ([Formula: see text], inversion; [Formula: see text], time-reversal) such as Cr2O3, even-layered CrI3 and possibly the pseudo-gap state in cuprates. In MnBi2Te4, this further opens the door for optical writing of a dissipationless circuit formed by topological edge states.
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Affiliation(s)
- Jian-Xiang Qiu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Christian Tzschaschel
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Junyeong Ahn
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Anyuan Gao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Houchen Li
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Xin-Yue Zhang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Barun Ghosh
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Yu-Xuan Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yu-Fei Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Damien Bérubé
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Thao Dinh
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Zhenhao Gong
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen, China
- International Quantum Academy, Shenzhen, China
| | - Shang-Wei Lien
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Sheng-Chin Ho
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Bahadur Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - David C Bell
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Hai-Zhou Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen, China
- International Quantum Academy, Shenzhen, China
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Brian B Zhou
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill, MA, USA
- Canadian Institute for Advanced Research, Toronto, Canada
| | | | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA.
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
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7
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Chapai R, Reddy PVS, Xing L, Graf DE, Karki AB, Chang TR, Jin R. Evidence for unconventional superconductivity and nontrivial topology in PdTe. Sci Rep 2023; 13:6824. [PMID: 37100848 PMCID: PMC10133450 DOI: 10.1038/s41598-023-33237-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/10/2023] [Indexed: 04/28/2023] Open
Abstract
PdTe is a superconductor with Tc ~ 4.25 K. Recently, evidence for bulk-nodal and surface-nodeless gap features has been reported in PdTe. Here, we investigate the physical properties of PdTe in both the normal and superconducting states via specific heat and magnetic torque measurements and first-principles calculations. Below Tc, the electronic specific heat initially decreases in T3 behavior (1.5 K < T < Tc) then exponentially decays. Using the two-band model, the superconducting specific heat can be well described with two energy gaps: one is 0.372 meV and another 1.93 meV. The calculated bulk band structure consists of two electron bands (α and β) and two hole bands (γ and η) at the Fermi level. Experimental detection of the de Haas-van Alphen (dHvA) oscillations allows us to identify four frequencies (Fα = 65 T, Fβ = 658 T, Fγ = 1154 T, and Fη = 1867 T for H // a), consistent with theoretical predictions. Nontrivial α and β bands are further identified via both calculations and the angle dependence of the dHvA oscillations. Our results suggest that PdTe is a candidate for unconventional superconductivity.
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Affiliation(s)
- Ramakanta Chapai
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA
| | | | - Lingyi Xing
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - David E Graf
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Amar B Karki
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, 70101, Taiwan
- Physics Division, National Center for Theoretical Sceinces, Taipei, 10617, Taiwan
| | - Rongying Jin
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA.
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, SC, 29208, USA.
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8
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Chiu WC, Chang G, Macam G, Belopolski I, Huang SM, Markiewicz R, Yin JX, Cheng ZJ, Lee CC, Chang TR, Chuang FC, Xu SY, Lin H, Hasan MZ, Bansil A. Causal structure of interacting Weyl fermions in condensed matter systems. Nat Commun 2023; 14:2228. [PMID: 37076531 PMCID: PMC10115776 DOI: 10.1038/s41467-023-37931-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/30/2023] [Indexed: 04/21/2023] Open
Abstract
The spacetime light cone is central to the definition of causality in the theory of relativity. Recently, links between relativistic and condensed matter physics have been uncovered, where relativistic particles can emerge as quasiparticles in the energy-momentum space of matter. Here, we unveil an energy-momentum analogue of the spacetime light cone by mapping time to energy, space to momentum, and the light cone to the Weyl cone. We show that two Weyl quasiparticles can only interact to open a global energy gap if they lie in each other's energy-momentum dispersion cones-analogous to two events that can only have a causal connection if they lie in each other's light cones. Moreover, we demonstrate that the causality of surface chiral modes in quantum matter is entangled with the causality of bulk Weyl fermions. Furthermore, we identify a unique quantum horizon region and an associated 'thick horizon' in the emergent causal structure.
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Grants
- NRF-NRFF13-2021-0010 National Research Foundation Singapore (National Research Foundation-Prime Minister's office, Republic of Singapore)
- FA9550- 20-1-0322 United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research (AF Office of Scientific Research)
- FA9550- 20-1-0322 United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research (AF Office of Scientific Research)
- FA9550-20-1-0322 United States Department of Defense | United States Air Force | AFMC | Air Force Office of Scientific Research (AF Office of Scientific Research)
- MOST-107-2628-M-110-001-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST-110-2112-M-110-013-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST 108-2112-M-110-013- MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST 110-2112-M-032-016-MY2. Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST110-2636-M-006-016 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST107-2627-E-006-001 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST-107-2628-M-110-001-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST-110-2112-M-110-013-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST 109-2112-M-001-014-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- GBMF4547 Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)
- GBMF9461 Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)
- GBMF4547 Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)
- GBMF9461 Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)
- DE-AC0207CH11358 DOE | LDRD | Ames Laboratory (Ames Lab)
- ECCS-2025158 National Science Foundation (NSF)
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Affiliation(s)
- Wei-Chi Chiu
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore, Singapore.
| | - Gennevieve Macam
- National Institute of Physics, University of the Philippines, Diliman, Quezon City, 1101, Philippines
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
- Center for Theoretical and Computational Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Robert Markiewicz
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
| | - Jia-Xin Yin
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Chi-Cheng Lee
- Department of Physics, Tamkang University, Tamsui, New Taipei, 251301, Taiwan
| | - Tay-Rong Chang
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan
| | - Feng-Chuan Chuang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
- Center for Theoretical and Computational Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, 115201, Taiwan
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
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9
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Cook J, Mardanya S, Lu Q, Conner C, Snyder M, Zhang X, McMillen J, Watson G, Chang TR, Bian G. Observation of Gapped Topological Surface States and Isolated Surface Resonances in PdTe 2 Ultrathin Films. Nano Lett 2023; 23:1752-1757. [PMID: 36825889 DOI: 10.1021/acs.nanolett.2c04511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The superconductor PdTe2 is known to host bulk Dirac bands and topological surface states. The coexistence of superconductivity and topological surface states makes PdTe2 a promising platform for exploring topological superconductivity and Majorana bound states. In this work, we report the spectroscopic characterization of ultrathin PdTe2 films with thickness down to three monolayers (ML). In the 3 ML PdTe2 film, we observed spin-polarized surface resonance states, which are isolated from the bulk bands due to the quantum size effects. In addition, the hybridization of surface states on opposite faces leads to a thickness-dependent gap in the topological surface Dirac bands. Our photoemission results show clearly that the size of the hybridization gap increases as the film thickness is reduced. The observation of isolated surface resonances and gapped topological surface states sheds light on the applications of PdTe2 quantum films in spintronics and topological quantum computation.
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Affiliation(s)
- Jacob Cook
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Sougata Mardanya
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Qiangsheng Lu
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Clayton Conner
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Matthew Snyder
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Xiaoqian Zhang
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - James McMillen
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Geoff Watson
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 70101, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
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10
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Cochran TA, Belopolski I, Manna K, Yahyavi M, Liu Y, Sanchez DS, Cheng ZJ, Yang XP, Multer D, Yin JX, Borrmann H, Chikina A, Krieger JA, Sánchez-Barriga J, Le Fèvre P, Bertran F, Strocov VN, Denlinger JD, Chang TR, Jia S, Felser C, Lin H, Chang G, Hasan MZ. Visualizing Higher-Fold Topology in Chiral Crystals. Phys Rev Lett 2023; 130:066402. [PMID: 36827563 DOI: 10.1103/physrevlett.130.066402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/18/2022] [Accepted: 12/14/2022] [Indexed: 06/18/2023]
Abstract
Novel topological phases of matter are fruitful platforms for the discovery of unconventional electromagnetic phenomena. Higher-fold topology is one example, where the low-energy description goes beyond standard model analogs. Despite intensive experimental studies, conclusive evidence remains elusive for the multigap topological nature of higher-fold chiral fermions. In this Letter, we leverage a combination of fine-tuned chemical engineering and photoemission spectroscopy with photon energy contrast to discover the higher-fold topology of a chiral crystal. We identify all bulk branches of a higher-fold chiral fermion for the first time, critically important for allowing us to explore unique Fermi arc surface states in multiple interband gaps, which exhibit an emergent ladder structure. Through designer chemical gating of the samples in combination with our measurements, we uncover an unprecedented multigap bulk boundary correspondence. Our demonstration of multigap electronic topology will propel future research on unconventional topological responses.
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Affiliation(s)
- Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Mohammad Yahyavi
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Yiyuan Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Xian P Yang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Alla Chikina
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Jonas A Krieger
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Jaime Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein Strasse 15, 12489 Berlin, Germany
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Patrick Le Fèvre
- SOLEIL Synchrotron, L'Orme des Merisiers, Départementale 128, F-91190 Saint-Aubin, France
| | - François Bertran
- SOLEIL Synchrotron, L'Orme des Merisiers, Départementale 128, F-91190 Saint-Aubin, France
| | | | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Shuang Jia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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11
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Yang XP, Zhong Y, Mardanya S, Cochran TA, Chapai R, Mine A, Zhang J, Sánchez-Barriga J, Cheng ZJ, Clark OJ, Yin JX, Blawat J, Cheng G, Belopolski I, Nagashima T, Najafzadeh S, Gao S, Yao N, Bansil A, Jin R, Chang TR, Shin S, Okazaki K, Hasan MZ. Coexistence of Bulk-Nodal and Surface-Nodeless Cooper Pairings in a Superconducting Dirac Semimetal. Phys Rev Lett 2023; 130:046402. [PMID: 36763428 DOI: 10.1103/physrevlett.130.046402] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
The interplay of nontrivial topology and superconductivity in condensed matter physics gives rise to exotic phenomena. However, materials are extremely rare where it is possible to explore the full details of the superconducting pairing. Here, we investigate the momentum dependence of the superconducting gap distribution in a novel Dirac material PdTe. Using high resolution, low temperature photoemission spectroscopy, we establish it as a spin-orbit coupled Dirac semimetal with the topological Fermi arc crossing the Fermi level on the (010) surface. This spin-textured surface state exhibits a fully gapped superconducting Cooper pairing structure below T_{c}∼4.5 K. Moreover, we find a node in the bulk near the Brillouin zone boundary, away from the topological Fermi arc. These observations not only demonstrate the band resolved electronic correlation between topological Fermi arc states and the way it induces Cooper pairing in PdTe, but also provide a rare case where surface and bulk states host a coexistence of nodeless and nodal gap structures enforced by spin-orbit coupling.
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Affiliation(s)
- Xian P Yang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Yigui Zhong
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Sougata Mardanya
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ramakanta Chapai
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Akifumi Mine
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Junyi Zhang
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Jaime Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein Strasse 15, Berlin 12489, Germany
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Oliver J Clark
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein Strasse 15, Berlin 12489, Germany
| | - Jia-Xin Yin
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Joanna Blawat
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Tsubaki Nagashima
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Sahand Najafzadeh
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Shiyuan Gao
- Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Rongying Jin
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Shik Shin
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Office of University Professor, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Material Innovation Research Center, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Kozo Okazaki
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Material Innovation Research Center, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Trans-scale Quantum Science Institute, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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12
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Cheng ZJ, Belopolski I, Tien HJ, Cochran TA, Yang XP, Ma W, Yin JX, Chen D, Zhang J, Jozwiak C, Bostwick A, Rotenberg E, Cheng G, Hossain MS, Zhang Q, Litskevich M, Jiang YX, Yao N, Schroeter NBM, Strocov VN, Lian B, Felser C, Chang G, Jia S, Chang TR, Hasan MZ. Visualization of Tunable Weyl Line in A-A Stacking Kagome Magnets. Adv Mater 2023; 35:e2205927. [PMID: 36385535 DOI: 10.1002/adma.202205927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Kagome magnets provide a fascinating platform for a plethora of topological quantum phenomena, in which the delicate interplay between frustrated crystal structure, magnetization, and spin-orbit coupling (SOC) can engender highly tunable topological states. Here, utilizing angle-resolved photoemission spectroscopy, the Weyl lines are directly visualized with strong out-of-plane dispersion in the A-A stacked kagome magnet GdMn6 Sn6 . Remarkably, the Weyl lines exhibit a strong magnetization-direction-tunable SOC gap and binding energy tunability after substituting Gd with Tb and Li, respectively. These results not only illustrate the magnetization direction and valence counting as efficient tuning knobs for realizing and controlling distinct 3D topological phases, but also demonstrate AMn6 Sn6 (A = rare earth, or Li, Mg, or Ca) as a versatile material family for exploring diverse emergent topological quantum responses.
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Affiliation(s)
- Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Xian P Yang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Wenlong Ma
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Dong Chen
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Junyi Zhang
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Md Shafayat Hossain
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Qi Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Maksim Litskevich
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Yu-Xiao Jiang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | | | - Vladimir N Strocov
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Biao Lian
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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13
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Yin JX, Jiang YX, Teng X, Hossain MS, Mardanya S, Chang TR, Ye Z, Xu G, Denner MM, Neupert T, Lienhard B, Deng HB, Setty C, Si Q, Chang G, Guguchia Z, Gao B, Shumiya N, Zhang Q, Cochran TA, Multer D, Yi M, Dai P, Hasan MZ. Discovery of Charge Order and Corresponding Edge State in Kagome Magnet FeGe. Phys Rev Lett 2022; 129:166401. [PMID: 36306757 DOI: 10.1103/physrevlett.129.166401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Kagome materials often host exotic quantum phases, including spin liquids, Chern gap, charge density wave, and superconductivity. Existing scanning microscopy studies of the kagome charge order have been limited to nonkagome surface layers. Here, we tunnel into the kagome lattice of FeGe to uncover features of the charge order. Our spectroscopic imaging identifies a 2×2 charge order in the magnetic kagome lattice, resembling that discovered in kagome superconductors. Spin mapping across steps of unit cell height demonstrates the existence of spin-polarized electrons with an antiferromagnetic stacking order. We further uncover the correlation between antiferromagnetism and charge order anisotropy, highlighting the unusual magnetic coupling of the charge order. Finally, we detect a pronounced edge state within the charge order energy gap, which is robust against the irregular shape fluctuations of the kagome lattice edges. We discuss our results with the theoretically considered topological features of the kagome charge order including unconventional magnetism and bulk-boundary correspondence.
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Affiliation(s)
- Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Yu-Xiao Jiang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Xiaokun Teng
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Md Shafayat Hossain
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Sougata Mardanya
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Zijin Ye
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Gang Xu
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - M Michael Denner
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Titus Neupert
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Benjamin Lienhard
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Han-Bin Deng
- Laboratory for Quantum Emergence, department of physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chandan Setty
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798, Singapore
| | - Zurab Guguchia
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Bin Gao
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Nana Shumiya
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Qi Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ming Yi
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
- Quantum Science Center, Oak Ridge, Tennessee 37830, USA
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14
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Shumiya N, Hossain MS, Yin JX, Wang Z, Litskevich M, Yoon C, Li Y, Yang Y, Jiang YX, Cheng G, Lin YC, Zhang Q, Cheng ZJ, Cochran TA, Multer D, Yang XP, Casas B, Chang TR, Neupert T, Yuan Z, Jia S, Lin H, Yao N, Balicas L, Zhang F, Yao Y, Hasan MZ. Evidence of a room-temperature quantum spin Hall edge state in a higher-order topological insulator. Nat Mater 2022; 21:1111-1115. [PMID: 35835819 DOI: 10.1038/s41563-022-01304-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Room-temperature realization of macroscopic quantum phases is one of the major pursuits in fundamental physics1,2. The quantum spin Hall phase3-6 is a topological quantum phase that features a two-dimensional insulating bulk and a helical edge state. Here we use vector magnetic field and variable temperature based scanning tunnelling microscopy to provide micro-spectroscopic evidence for a room-temperature quantum spin Hall edge state on the surface of the higher-order topological insulator Bi4Br4. We find that the atomically resolved lattice exhibits a large insulating gap of over 200 meV, and an atomically sharp monolayer step edge hosts an in-gap gapless state, suggesting topological bulk-boundary correspondence. An external magnetic field can gap the edge state, consistent with the time-reversal symmetry protection inherent in the underlying band topology. We further identify the geometrical hybridization of such edge states, which not only supports the Z2 topology of the quantum spin Hall state but also visualizes the building blocks of the higher-order topological insulator phase. Our results further encourage the exploration of high-temperature transport quantization of the putative topological phase reported here.
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Affiliation(s)
- Nana Shumiya
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Md Shafayat Hossain
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Maksim Litskevich
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Chiho Yoon
- Department of Physics, University of Texas at Dallas, Richardson, TX, USA
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Yongkai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Ying Yang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Yu-Xiao Jiang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | - Yen-Chuan Lin
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - Qi Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Xian P Yang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Brian Casas
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Titus Neupert
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - Zhujun Yuan
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China
- Beijing Academy of Quantum Information Sciences,, Beijing, China
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China
- Beijing Academy of Quantum Information Sciences,, Beijing, China
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | - Luis Balicas
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - Fan Zhang
- Department of Physics, University of Texas at Dallas, Richardson, TX, USA
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Quantum Science Center, Oak Ridge, TN, USA.
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15
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Lu Q, Cook J, Zhang X, Chen KY, Snyder M, Nguyen DT, Reddy PVS, Qin B, Zhan S, Zhao LD, Kowalczyk PJ, Brown SA, Chiang TC, Yang SA, Chang TR, Bian G. Realization of unpinned two-dimensional dirac states in antimony atomic layers. Nat Commun 2022; 13:4603. [PMID: 35933407 PMCID: PMC9357080 DOI: 10.1038/s41467-022-32327-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/26/2022] [Indexed: 11/24/2022] Open
Abstract
Two-dimensional (2D) Dirac states with linear dispersion have been observed in graphene and on the surface of topological insulators. 2D Dirac states discovered so far are exclusively pinned at high-symmetry points of the Brillouin zone, for example, surface Dirac states at \documentclass[12pt]{minimal}
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\begin{document}$$\overline{{{\Gamma }}}$$\end{document}Γ¯ in topological insulators Bi2Se(Te)3 and Dirac cones at K and \documentclass[12pt]{minimal}
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\begin{document}$$K^{\prime}$$\end{document}K′ points in graphene. The low-energy dispersion of those Dirac states are isotropic due to the constraints of crystal symmetries. In this work, we report the observation of novel 2D Dirac states in antimony atomic layers with phosphorene structure. The Dirac states in the antimony films are located at generic momentum points. This unpinned nature enables versatile ways such as lattice strains to control the locations of the Dirac points in momentum space. In addition, dispersions around the unpinned Dirac points are highly anisotropic due to the reduced symmetry of generic momentum points. The exotic properties of unpinned Dirac states make antimony atomic layers a new type of 2D Dirac semimetals that are distinct from graphene. In graphene and on the surfaces of many topological insulators, the Dirac cones are pinned to high symmetry points in reciprocal space. Here, the authors report that the Dirac cones in atomically-thin Sb layers occur at generic reciprocal-space points which can be tuned by lattice strain.
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Affiliation(s)
- Qiangsheng Lu
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Jacob Cook
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Xiaoqian Zhang
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Kyle Y Chen
- Rock Bridge High School, Columbia, MO, 65203, USA
| | - Matthew Snyder
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Duy Tung Nguyen
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | | | - Bingchao Qin
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Shaoping Zhan
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Li-Dong Zhao
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Pawel J Kowalczyk
- Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Lodz, 90-236 Lodz, Pomorska, 149/153, Poland.
| | - Simon A Brown
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Physical and Chemical Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Tai-Chang Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801-3080, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, IL, 61801-2902, USA
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA.
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16
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Xu X, Yin JX, Ma W, Tien HJ, Qiang XB, Reddy PVS, Zhou H, Shen J, Lu HZ, Chang TR, Qu Z, Jia S. Topological charge-entropy scaling in kagome Chern magnet TbMn6Sn6. Nat Commun 2022; 13:1197. [PMID: 35256604 PMCID: PMC8901788 DOI: 10.1038/s41467-022-28796-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/26/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractIn ordinary materials, electrons conduct both electricity and heat, where their charge-entropy relations observe the Mott formula and the Wiedemann-Franz law. In topological quantum materials, the transverse motion of relativistic electrons can be strongly affected by the quantum field arising around the topological fermions, where a simple model description of their charge-entropy relations remains elusive. Here we report the topological charge-entropy scaling in the kagome Chern magnet TbMn6Sn6, featuring pristine Mn kagome lattices with strong out-of-plane magnetization. Through both electric and thermoelectric transports, we observe quantum oscillations with a nontrivial Berry phase, a large Fermi velocity and two-dimensionality, supporting the existence of Dirac fermions in the magnetic kagome lattice. This quantum magnet further exhibits large anomalous Hall, anomalous Nernst, and anomalous thermal Hall effects, all of which persist to above room temperature. Remarkably, we show that the charge-entropy scaling relations of these anomalous transverse transports can be ubiquitously described by the Berry curvature field effects in a Chern-gapped Dirac model. Our work points to a model kagome Chern magnet for the proof-of-principle elaboration of the topological charge-entropy scaling.
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17
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Zou WJ, Guo MX, Wong JF, Huang ZP, Chia JM, Chen WN, Wang SX, Lin KY, Young LB, Lin YHG, Yahyavi M, Wu CT, Jeng HT, Lee SF, Chang TR, Hong M, Kwo J. Enormous Berry-Curvature-Based Anomalous Hall Effect in Topological Insulator (Bi,Sb) 2Te 3 on Ferrimagnetic Europium Iron Garnet beyond 400 K. ACS Nano 2022; 16:2369-2380. [PMID: 35099945 DOI: 10.1021/acsnano.1c08663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
To realize the quantum anomalous Hall effect (QAHE) at elevated temperatures, the approach of magnetic proximity effect (MPE) was adopted to break the time-reversal symmetry in the topological insulator (Bi0.3Sb0.7)2Te3 (BST) based heterostructures with a ferrimagnetic insulator europium iron garnet (EuIG) of perpendicular magnetic anisotropy. Here we demonstrate large anomalous Hall resistance (RAHE) exceeding 8 Ω (ρAHE of 3.2 μΩ·cm) at 300 K and sustaining to 400 K in 35 BST/EuIG samples, surpassing the past record of 0.28 Ω (ρAHE of 0.14 μΩ·cm) at 300 K. The large RAHE is attributed to an atomically abrupt, Fe-rich interface between BST and EuIG. Importantly, the gate dependence of the AHE loops shows no sign change with varying chemical potential. This observation is supported by our first-principles calculations via applying a gradient Zeeman field plus a contact potential on BST. Our calculations further demonstrate that the AHE in this heterostructure is attributed to the intrinsic Berry curvature. Furthermore, for gate-biased 4 nm BST on EuIG, a pronounced topological Hall effect-like (THE-like) feature coexisting with AHE is observed at the negative top-gate voltage up to 15 K. Interface tuning with theoretical calculations has realized topologically distinct phenomena in tailored magnetic TI-based heterostructures.
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Affiliation(s)
- Wei-Jhih Zou
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Meng-Xin Guo
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jyun-Fong Wong
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Zih-Ping Huang
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Jui-Min Chia
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wei-Nien Chen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Sheng-Xin Wang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Keng-Yung Lin
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Lawrence Boyu Young
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Yen-Hsun Glen Lin
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Mohammad Yahyavi
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chien-Ting Wu
- Materials Analysis Division, Taiwan Semiconductor Research Institute, National Applied Research Laboratories, Hsinchu 300091, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Shang-Fan Lee
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
| | - Minghwei Hong
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Jueinai Kwo
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
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18
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Su SH, Chuang PY, Chen HY, Weng SC, Chen WC, Tsuei KD, Lee CK, Yu SH, Chou MMC, Tu LW, Jeng HT, Tu CM, Luo CW, Cheng CM, Chang TR, Huang JCA. Topological Proximity-Induced Dirac Fermion in Two-Dimensional Antimonene. ACS Nano 2021; 15:15085-15095. [PMID: 34435764 DOI: 10.1021/acsnano.1c05454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Antimonene is a promising two-dimensional (2D) material that is calculated to have a significant fundamental bandgap usable for advanced applications such as field-effect transistors, photoelectric devices, and the quantum-spin Hall (QSH) state. Herein, we demonstrate a phenomenon termed topological proximity effect, which occurs between a 2D material and a three-dimensional (3D) topological insulator (TI). We provide strong evidence derived from hydrogen etching on Sb2Te3 that large-area and well-ordered antimonene presents a 2D topological state. Delicate analysis with a scanning tunneling microscope of the evolutionary intermediates reveals that hydrogen etching on Sb2Te3 resulted in the formation of a large area of antimonene with a buckled structure. A topological state formed in the antimonene/Sb2Te3 heterostructure was confirmed with angle-resolved photoemission spectra and density-functional theory calculations; in particular, the Dirac point was located almost at the Fermi level. The results reveal that Dirac fermions are indeed realized at the interface of a 2D normal insulator (NI) and a 3D TI as a result of strong hybridization between antimonene and Sb2Te3. Our work demonstrates that the position of the Dirac point and the shape of the Dirac surface state can be tuned by varying the energy position of the NI valence band, which modifies the direction of the spin texture of Sb-BL/Sb2Te3 via varying the Fermi level. This topological phase in 2D-material engineering has generated a paradigm in that the topological proximity effect at the NI/TI interface has been realized, which demonstrates a way to create QSH systems in 2D-material TI heterostructures.
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Affiliation(s)
- Shu Hsuan Su
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
| | - Pei-Yu Chuang
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Hsin-Yu Chen
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Wei-Chuan Chen
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Ku-Ding Tsuei
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Chao-Kuei Lee
- Department of Photonics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Research Center for Applied Sciences, Academia Sinica, 187 Academia Road, Taipei 11529, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Shih-Hsun Yu
- Department of Materials and Optoelectronics Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Mitch M-C Chou
- Department of Materials and Optoelectronics Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Li-Wei Tu
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Chien-Ming Tu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
| | - Chih-Wei Luo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106335, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Jung-Chun Andrew Huang
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
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19
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Gao A, Liu YF, Hu C, Qiu JX, Tzschaschel C, Ghosh B, Ho SC, Bérubé D, Chen R, Sun H, Zhang Z, Zhang XY, Wang YX, Wang N, Huang Z, Felser C, Agarwal A, Ding T, Tien HJ, Akey A, Gardener J, Singh B, Watanabe K, Taniguchi T, Burch KS, Bell DC, Zhou BB, Gao W, Lu HZ, Bansil A, Lin H, Chang TR, Fu L, Ma Q, Ni N, Xu SY. Layer Hall effect in a 2D topological axion antiferromagnet. Nature 2021; 595:521-525. [PMID: 34290425 DOI: 10.1038/s41586-021-03679-w] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/27/2021] [Indexed: 11/10/2022]
Abstract
Whereas ferromagnets have been known and used for millennia, antiferromagnets were only discovered in the 1930s1. At large scale, because of the absence of global magnetization, antiferromagnets may seem to behave like any non-magnetic material. At the microscopic level, however, the opposite alignment of spins forms a rich internal structure. In topological antiferromagnets, this internal structure leads to the possibility that the property known as the Berry phase can acquire distinct spatial textures2,3. Here we study this possibility in an antiferromagnetic axion insulator-even-layered, two-dimensional MnBi2Te4-in which spatial degrees of freedom correspond to different layers. We observe a type of Hall effect-the layer Hall effect-in which electrons from the top and bottom layers spontaneously deflect in opposite directions. Specifically, under zero electric field, even-layered MnBi2Te4 shows no anomalous Hall effect. However, applying an electric field leads to the emergence of a large, layer-polarized anomalous Hall effect of about 0.5e2/h (where e is the electron charge and h is Planck's constant). This layer Hall effect uncovers an unusual layer-locked Berry curvature, which serves to characterize the axion insulator state. Moreover, we find that the layer-locked Berry curvature can be manipulated by the axion field formed from the dot product of the electric and magnetic field vectors. Our results offer new pathways to detect and manipulate the internal spatial structure of fully compensated topological antiferromagnets4-9. The layer-locked Berry curvature represents a first step towards spatial engineering of the Berry phase through effects such as layer-specific moiré potential.
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Affiliation(s)
- Anyuan Gao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Yu-Fei Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jian-Xiang Qiu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Christian Tzschaschel
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Barun Ghosh
- Department of Physics, Indian Institute of Technology, Kanpur, India.,Department of Physics, Northeastern University, Boston, MA, USA
| | - Sheng-Chin Ho
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Damien Bérubé
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Rui Chen
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Haipeng Sun
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xin-Yue Zhang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yu-Xuan Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Naizhou Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zumeng Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Amit Agarwal
- Department of Physics, Indian Institute of Technology, Kanpur, India
| | - Thomas Ding
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
| | - Austin Akey
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Jules Gardener
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Bahadur Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenneth S Burch
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - David C Bell
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA.,Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Brian B Zhou
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Hai-Zhou Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan.,Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan.,Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
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20
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Kumar D, Hsu CH, Sharma R, Chang TR, Yu P, Wang J, Eda G, Liang G, Yang H. Room-temperature nonlinear Hall effect and wireless radiofrequency rectification in Weyl semimetal TaIrTe 4. Nat Nanotechnol 2021; 16:421-425. [PMID: 33495620 DOI: 10.1038/s41565-020-00839-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
The nonlinear Hall effect (NLHE), the phenomenon in which a transverse voltage can be produced without a magnetic field, provides a potential alternative for rectification or frequency doubling1,2. However, the low-temperature detection of the NLHE limits its applications3,4. Here, we report the room-temperature NLHE in a type-II Weyl semimetal TaIrTe4, which hosts a robust NLHE due to broken inversion symmetry and large band overlapping at the Fermi level. We also observe a temperature-induced sign inversion of the NLHE in TaIrTe4. Our theoretical calculations suggest that the observed sign inversion is a result of a temperature-induced shift in the chemical potential, indicating a direct correlation of the NLHE with the electronic structure at the Fermi surface. Finally, on the basis of the observed room-temperature NLHE in TaIrTe4 we demonstrate the wireless radiofrequency (RF) rectification with zero external bias and magnetic field. This work opens a door to realizing room-temperature applications based on the NLHE in Weyl semimetals.
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Affiliation(s)
- Dushyant Kumar
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Chuang-Han Hsu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Raghav Sharma
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, Taiwan
| | - Peng Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Junyong Wang
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Goki Eda
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Gengchiau Liang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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21
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Gui X, Chang TR, Wei K, Daum MJ, Graf DE, Baumbach RE, Mourigal M, Xie W. A Novel Magnetic Material by Design: Observation of Yb 3+ with Spin-1/2 in Yb x Pt 5P. ACS Cent Sci 2020; 6:2023-2030. [PMID: 33274279 PMCID: PMC7706091 DOI: 10.1021/acscentsci.0c00691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Indexed: 06/12/2023]
Abstract
The localized f-electrons enrich the magnetic properties in rare-earth-based intermetallics. Among those, compounds with heavier 4d and 5d transition metals are even more fascinating because anomalous electronic properties may be induced by the hybridization of 4f and itinerant conduction electrons primarily from the d orbitals. Here, we describe the observation of trivalent Yb3+ with S = 1/2 at low temperatures in Yb x Pt5P, the first of a new family of materials. Yb x Pt5P (0.23 ≤ x ≤ 0.96) phases were synthesized and structurally characterized. They exhibit a large homogeneity width with the Yb ratio exclusively occupying the 1a site in the anti-CeCoIn5 structure. Moreover, a sudden resistivity drop could be found in Yb x Pt5P below ∼0.6 K, which requires further investigation. First-principles electronic structure calculations substantiate the antiferromagnetic ground state and indicate that two-dimensional nesting around the Fermi level may give rise to exotic physical properties, such as superconductivity. Yb x Pt5P appears to be a unique case among materials.
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Affiliation(s)
- Xin Gui
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Tay-Rong Chang
- Department
of Physics, National Cheng Kung University, Tainan, Taiwan 70101
- Center
for Quantum Frontiers of Research & Technology (QFort), Tainan, Taiwan 70101
| | - Kaya Wei
- National
High Magnetic Field Laboratory, Tallahassee, Florida 32306, United States
| | - Marcus J. Daum
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30322, United States
| | - David E. Graf
- National
High Magnetic Field Laboratory, Tallahassee, Florida 32306, United States
| | - Ryan E. Baumbach
- National
High Magnetic Field Laboratory, Tallahassee, Florida 32306, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Martin Mourigal
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30322, United States
| | - Weiwei Xie
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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22
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Yin JX, Shumiya N, Mardanya S, Wang Q, Zhang SS, Tien HJ, Multer D, Jiang Y, Cheng G, Yao N, Wu S, Wu D, Deng L, Ye Z, He R, Chang G, Liu Z, Jiang K, Wang Z, Neupert T, Agarwal A, Chang TR, Chu CW, Lei H, Hasan MZ. Fermion-boson many-body interplay in a frustrated kagome paramagnet. Nat Commun 2020; 11:4003. [PMID: 32778651 PMCID: PMC7417595 DOI: 10.1038/s41467-020-17464-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 07/01/2020] [Indexed: 11/09/2022] Open
Abstract
Kagome-nets, appearing in electronic, photonic and cold-atom systems, host frustrated fermionic and bosonic excitations. However, it is rare to find a system to study their fermion-boson many-body interplay. Here we use state-of-the-art scanning tunneling microscopy/spectroscopy to discover unusual electronic coupling to flat-band phonons in a layered kagome paramagnet, CoSn. We image the kagome structure with unprecedented atomic resolution and observe the striking bosonic mode interacting with dispersive kagome electrons near the Fermi surface. At this mode energy, the fermionic quasi-particle dispersion exhibits a pronounced renormalization, signaling a giant coupling to bosons. Through the self-energy analysis, first-principles calculation, and a lattice vibration model, we present evidence that this mode arises from the geometrically frustrated phonon flat-band, which is the lattice bosonic analog of the kagome electron flat-band. Our findings provide the first example of kagome bosonic mode (flat-band phonon) in electronic excitations and its strong interaction with fermionic degrees of freedom in kagome-net materials.
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Affiliation(s)
- J-X Yin
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
| | - Nana Shumiya
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Sougata Mardanya
- Department of Physics, National Cheng Kung University, 701, Tainan, Taiwan
| | - Qi Wang
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices, Renmin University of China, 100872, Beijing, China
| | - Songtian S Zhang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, 701, Tainan, Taiwan
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Yuxiao Jiang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials (PRISM), Princeton University, Princeton, NJ, 08544, USA
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials (PRISM), Princeton University, Princeton, NJ, 08544, USA
| | - Shangfei Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Desheng Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Liangzi Deng
- Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX, 77204-5002, USA
| | - Zhipeng Ye
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Rui He
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Guoqing Chang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Zhonghao Liu
- State Key Laboratory of Functional Materials for Informatics and Center for Excellence in Superconducting Electronics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Kun Jiang
- Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA
| | - Titus Neupert
- Department of Physics, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
| | - Amit Agarwal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, 701, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), 701, Tainan, Taiwan
- Physics Division, National Center for Theoretical Sciences, 30013, Hsinchu, Taiwan
| | - Ching-Wu Chu
- Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX, 77204-5002, USA
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices, Renmin University of China, 100872, Beijing, China
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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23
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Zhang SS, Yin JX, Ikhlas M, Tien HJ, Wang R, Shumiya N, Chang G, Tsirkin SS, Shi Y, Yi C, Guguchia Z, Li H, Wang W, Chang TR, Wang Z, Yang YF, Neupert T, Nakatsuji S, Hasan MZ. Many-Body Resonance in a Correlated Topological Kagome Antiferromagnet. Phys Rev Lett 2020; 125:046401. [PMID: 32794798 DOI: 10.1103/physrevlett.125.046401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
We use scanning tunneling microscopy to elucidate the atomically resolved electronic structure in the strongly correlated kagome Weyl antiferromagnet Mn_{3}Sn. In stark contrast to its broad single-particle electronic structure, we observe a pronounced resonance with a Fano line shape at the Fermi level resembling the many-body Kondo resonance. We find that this resonance does not arise from the step edges or atomic impurities but the intrinsic kagome lattice. Moreover, the resonance is robust against the perturbation of a vector magnetic field, but broadens substantially with increasing temperature, signaling strongly interacting physics. We show that this resonance can be understood as the result of geometrical frustration and strong correlation based on the kagome lattice Hubbard model. Our results point to the emergent many-body resonance behavior in a topological kagome magnet.
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Affiliation(s)
- Songtian Sonia Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy, Department of Physics, Princeton University, Princeton 08544, New Jersey, USA
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy, Department of Physics, Princeton University, Princeton 08544, New Jersey, USA
| | - Muhammad Ikhlas
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Rui Wang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Nana Shumiya
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy, Department of Physics, Princeton University, Princeton 08544, New Jersey, USA
| | - Guoqing Chang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy, Department of Physics, Princeton University, Princeton 08544, New Jersey, USA
| | - Stepan S Tsirkin
- Department of Physics, University of Zurich, Zurich 8057, Switzerland
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changjiang Yi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zurab Guguchia
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI CH-5232, Switzerland
| | - Hang Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenhong Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Titus Neupert
- Department of Physics, University of Zurich, Zurich 8057, Switzerland
| | - Satoru Nakatsuji
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
- Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy, Department of Physics, Princeton University, Princeton 08544, New Jersey, USA
- Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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24
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Hu C, Ding L, Gordon KN, Ghosh B, Tien HJ, Li H, Linn AG, Lien SW, Huang CY, Mackey S, Liu J, Reddy PVS, Singh B, Agarwal A, Bansil A, Song M, Li D, Xu SY, Lin H, Cao H, Chang TR, Dessau D, Ni N. Realization of an intrinsic ferromagnetic topological state in MnBi 8Te 13. Sci Adv 2020; 6:eaba4275. [PMID: 32743072 PMCID: PMC7375807 DOI: 10.1126/sciadv.aba4275] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/09/2020] [Indexed: 05/13/2023]
Abstract
Novel magnetic topological materials pave the way for studying the interplay between band topology and magnetism. However, an intrinsically ferromagnetic topological material with only topological bands at the charge neutrality energy has so far remained elusive. Using rational design, we synthesized MnBi8Te13, a natural heterostructure with [MnBi2Te4] and [Bi2Te3] layers. Thermodynamic, transport, and neutron diffraction measurements show that despite the adjacent [MnBi2Te4] being 44.1 Å apart, MnBi8Te13 manifests long-range ferromagnetism below 10.5 K with strong coupling between magnetism and charge carriers. First-principles calculations and angle-resolved photoemission spectroscopy measurements reveal it is an axion insulator with sizable surface hybridization gaps. Our calculations further demonstrate the hybridization gap persists in the two-dimensional limit with a nontrivial Chern number. Therefore, as an intrinsic ferromagnetic axion insulator with clean low-energy band structures, MnBi8Te13 serves as an ideal system to investigate rich emergent phenomena, including the quantized anomalous Hall effect and quantized magnetoelectric effect.
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Affiliation(s)
- Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lei Ding
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Kyle N. Gordon
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Barun Ghosh
- Department of Physics, Indian Institute of Technology-Kanpur, Kanpur 208016, India
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Haoxiang Li
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - A. Garrison Linn
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Shang-Wei Lien
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Cheng-Yi Huang
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Scott Mackey
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jinyu Liu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - Bahadur Singh
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Amit Agarwal
- Department of Physics, Indian Institute of Technology-Kanpur, Kanpur 208016, India
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Miao Song
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Dongsheng Li
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Huibo Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
| | - Dan Dessau
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Center for Experiments on Quantum Materials, University of Colorado, Boulder, CO 80309, USA
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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25
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Chang TR, Šuta D, Chiu TW. Responses of midbrain auditory neurons to two different environmental sounds-A new approach on cross-sound modeling. Biosystems 2019; 187:104021. [PMID: 31574292 DOI: 10.1016/j.biosystems.2019.104021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/07/2019] [Accepted: 08/19/2019] [Indexed: 11/29/2022]
Abstract
When modeling auditory responses to environmental sounds, results are satisfactory if both training and testing are restricted to datasets of one type of sound. To predict 'cross-sound' responses (i.e., to predict the response to one type of sound e.g., rat Eating sound, after training with another type of sound e.g., rat Drinking sound), performance is typically poor. Here we implemented a novel approach to improve such cross-sound modeling (single unit datasets were collected at the auditory midbrain of anesthetized rats). The method had two key features: (a) population responses (e.g., average of 32 units) instead of responses of individual units were analyzed; and (b) the long sound segment was first divided into short segments (single sound-bouts), their similarity was then computed over a new metric involving the response (called Stimulus Response Model map or SRM map), and finally similar sound-bouts (regardless of sound type) and their associated responses (peri-stimulus time histograms, PSTHs) were modelled. Specifically, a committee machine model (artificial neural networks with 20 stratified spectral inputs) was trained with datasets from one sound type before predicting PSTH responses to another sound type. Model performance was markedly improved up to 92%. Results also suggested the involvement of different neural mechanisms in generating the early and late responses to amplitude transients in the broad-band environmental sounds. We concluded that it is possible to perform rather satisfactory cross-sound modeling on datasets grouped together based on their similarities in terms of the new metric of SRM map.
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Affiliation(s)
- T R Chang
- Department of Computer Science and Information Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan, ROC
| | - D Šuta
- Department of Cognitive Systems and Neurosciences, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University, Prague, Czech Republic; Department of Auditory Neuroscience, Academy of Sciences of the Czech Republic, Czech Republic
| | - T W Chiu
- Department of Biological Science and Technology, National Chiao-Tung University, Hsinchu, Taiwan, ROC; Center For Intelligent Drug Systems and Smart Bio-devices (IDS2B), National Chiao-Tung University, Hsinchu, Taiwan, ROC.
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26
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Belopolski I, Manna K, Sanchez DS, Chang G, Ernst B, Yin J, Zhang SS, Cochran T, Shumiya N, Zheng H, Singh B, Bian G, Multer D, Litskevich M, Zhou X, Huang SM, Wang B, Chang TR, Xu SY, Bansil A, Felser C, Lin H, Hasan MZ. Discovery of topological Weyl fermion lines and drumhead surface states in a room temperature magnet. Science 2019; 365:1278-1281. [DOI: 10.1126/science.aav2327] [Citation(s) in RCA: 252] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 08/14/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Daniel S. Sanchez
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Guoqing Chang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Benedikt Ernst
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Jiaxin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Songtian S. Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Tyler Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Nana Shumiya
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Hao Zheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Bahadur Singh
- SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science and Technology, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Maksim Litskevich
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Xiaoting Zhou
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Baokai Wang
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - M. Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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27
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Abstract
Bismuth-based materials have been instrumental in the development of topological physics, even though bulk bismuth itself has been long thought to be topologically trivial. A recent study has, however, shown that bismuth is in fact a higher-order topological insulator featuring one-dimensional (1D) topological hinge states protected by threefold rotational and inversion symmetries. In this paper, we uncover another hidden facet of the band topology of bismuth by showing that bismuth is also a first-order topological crystalline insulator protected by a twofold rotational symmetry. As a result, its [Formula: see text] surface exhibits a pair of gapless Dirac surface states. Remarkably, these surface Dirac cones are "unpinned" in the sense that they are not restricted to locate at specific k points in the [Formula: see text] surface Brillouin zone. These unpinned 2D Dirac surface states could be probed directly via various spectroscopic techniques. Our analysis also reveals the presence of a distinct, previously uncharacterized set of 1D topological hinge states protected by the twofold rotational symmetry. Our study thus provides a comprehensive understanding of the topological band structure of bismuth.
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Affiliation(s)
- Chuang-Han Hsu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546
- Department of Physics, National University of Singapore, Singapore 117542
| | - Xiaoting Zhou
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), Tainan 701, Taiwan
| | - Qiong Ma
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115
| | - Su-Yang Xu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139;
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139;
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28
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Gui X, Pletikosic I, Cao H, Tien HJ, Xu X, Zhong R, Wang G, Chang TR, Jia S, Valla T, Xie W, Cava RJ. A New Magnetic Topological Quantum Material Candidate by Design. ACS Cent Sci 2019; 5:900-910. [PMID: 31139726 PMCID: PMC6535778 DOI: 10.1021/acscentsci.9b00202] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Indexed: 05/31/2023]
Abstract
Magnetism, when combined with an unconventional electronic band structure, can give rise to forefront electronic properties such as the quantum anomalous Hall effect, axion electrodynamics, and Majorana fermions. Here we report the characterization of high-quality crystals of EuSn2P2, a new quantum material specifically designed to engender unconventional electronic states plus magnetism. EuSn2P2 has a layered, Bi2Te3-type structure. Ferromagnetic interactions dominate the Curie-Weiss susceptibility, but a transition to antiferromagnetic ordering occurs near 30 K. Neutron diffraction reveals that this is due to two-dimensional ferromagnetic spin alignment within individual Eu layers and antiferromagnetic alignment between layers-this magnetic state surrounds the Sn-P layers at low temperatures. The bulk electrical resistivity is sensitive to the magnetism. Electronic structure calculations reveal that EuSn2P2 might be a strong topological insulator, which can be a new magnetic topological quantum material (MTQM) candidate. The calculations show that surface states should be present, and they are indeed observed by angle-resolved photoelectron spectroscopy (ARPES) measurements.
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Affiliation(s)
- Xin Gui
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Ivo Pletikosic
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
- Condensed
Matter Physics and Materials Science, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - Huibo Cao
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hung-Ju Tien
- Department
of Physics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Xitong Xu
- International
Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People’s Republic
of China
| | - Ruidan Zhong
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Guangqiang Wang
- International
Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People’s Republic
of China
| | - Tay-Rong Chang
- Department
of Physics, National Cheng Kung University, Tainan 70101, Taiwan
- Center for Quantum
Frontiers of Research & Technology (QFort), Tainan 701, Taiwan
| | - Shuang Jia
- International
Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People’s Republic
of China
- Collaborative
Innovation Center of Quantum Matter, Beijing 100871, People’s
Republic of China
- CAS
Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Tonica Valla
- Condensed
Matter Physics and Materials Science, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - Weiwei Xie
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Robert J. Cava
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
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29
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Sanchez DS, Belopolski I, Cochran TA, Xu X, Yin JX, Chang G, Xie W, Manna K, Süß V, Huang CY, Alidoust N, Multer D, Zhang SS, Shumiya N, Wang X, Wang GQ, Chang TR, Felser C, Xu SY, Jia S, Lin H, Hasan MZ. Topological chiral crystals with helicoid-arc quantum states. Nature 2019; 567:500-505. [DOI: 10.1038/s41586-019-1037-2] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/10/2019] [Indexed: 11/09/2022]
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30
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Ma Q, Xu SY, Shen H, MacNeill D, Fatemi V, Chang TR, Mier Valdivia AM, Wu S, Du Z, Hsu CH, Fang S, Gibson QD, Watanabe K, Taniguchi T, Cava RJ, Kaxiras E, Lu HZ, Lin H, Fu L, Gedik N, Jarillo-Herrero P. Observation of the nonlinear Hall effect under time-reversal-symmetric conditions. Nature 2018; 565:337-342. [DOI: 10.1038/s41586-018-0807-6] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 11/14/2018] [Indexed: 11/09/2022]
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31
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Chang G, Wieder BJ, Schindler F, Sanchez DS, Belopolski I, Huang SM, Singh B, Wu D, Chang TR, Neupert T, Xu SY, Lin H, Hasan MZ. Topological quantum properties of chiral crystals. Nat Mater 2018; 17:978-985. [PMID: 30275564 DOI: 10.1038/s41563-018-0169-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Accepted: 08/15/2018] [Indexed: 05/02/2023]
Abstract
Chiral crystals are materials with a lattice structure that has a well-defined handedness due to the lack of inversion, mirror or other roto-inversion symmetries. Although it has been shown that the presence of crystalline symmetries can protect topological band crossings, the topological electronic properties of chiral crystals remain largely uncharacterized. Here we show that Kramers-Weyl fermions are a universal topological electronic property of all non-magnetic chiral crystals with spin-orbit coupling and are guaranteed by structural chirality, lattice translation and time-reversal symmetry. Unlike conventional Weyl fermions, they appear at time-reversal-invariant momenta. We identify representative chiral materials in 33 of the 65 chiral space groups in which Kramers-Weyl fermions are relevant to the low-energy physics. We determine that all point-like nodal degeneracies in non-magnetic chiral crystals with relevant spin-orbit coupling carry non-trivial Chern numbers. Kramers-Weyl materials can exhibit a monopole-like electron spin texture and topologically non-trivial bulk Fermi surfaces over an unusually large energy window.
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Affiliation(s)
- Guoqing Chang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Benjamin J Wieder
- Department of Physics, Princeton University, Princeton, NJ, USA
- Nordita, Center for Quantum Materials, KTH Royal Institute of Technology and Stockholm University, Stockholm, Sweden
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Frank Schindler
- Department of Physics, University of Zurich, Zurich, Switzerland
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Bahadur Singh
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Di Wu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
| | - Titus Neupert
- Department of Physics, University of Zurich, Zurich, Switzerland
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
- Department of Physics, National University of Singapore, Singapore, Singapore.
- Institute of Physics, Academia Sinica, Taipei, Taiwan.
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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32
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Zhu Z, Chang TR, Huang CY, Pan H, Nie XA, Wang XZ, Jin ZT, Xu SY, Huang SM, Guan DD, Wang S, Li YY, Liu C, Qian D, Ku W, Song F, Lin H, Zheng H, Jia JF. Quasiparticle interference and nonsymmorphic effect on a floating band surface state of ZrSiSe. Nat Commun 2018; 9:4153. [PMID: 30297777 PMCID: PMC6175950 DOI: 10.1038/s41467-018-06661-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 09/18/2018] [Indexed: 11/09/2022] Open
Abstract
Non-symmorphic crystals are generating great interest as they are commonly found in quantum materials, like iron-based superconductors, heavy-fermion compounds, and topological semimetals. A new type of surface state, a floating band, was recently discovered in the nodal-line semimetal ZrSiSe, but also exists in many non-symmorphic crystals. Little is known about its physical properties. Here, we employ scanning tunneling microscopy to measure the quasiparticle interference of the floating band state on ZrSiSe (001) surface and discover rotational symmetry breaking interference, healing effect and half-missing-type anomalous Umklapp scattering. Using simulation and theoretical analysis we establish that the phenomena are characteristic properties of a floating band surface state. Moreover, we uncover that the half-missing Umklapp process is derived from the glide mirror symmetry, thus identify a non-symmorphic effect on quasiparticle interferences. Our results may pave a way towards potential new applications of nanoelectronics.
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Affiliation(s)
- Zhen Zhu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Cheng-Yi Huang
- Institute of Physics, Academia Sinica, Taipei City, 11529, Taiwan
| | - Haiyang Pan
- College of Physics, Nanjing University, Nanjing, 210093, China
| | - Xiao-Ang Nie
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xin-Zhe Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhe-Ting Jin
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Su-Yang Xu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan
| | - Dan-Dan Guan
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Shiyong Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yao-Yi Li
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Canhua Liu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Dong Qian
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Wei Ku
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Fengqi Song
- College of Physics, Nanjing University, Nanjing, 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei City, 11529, Taiwan
| | - Hao Zheng
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Jin-Feng Jia
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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33
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Yin JX, Zhang SS, Li H, Jiang K, Chang G, Zhang B, Lian B, Xiang C, Belopolski I, Zheng H, Cochran TA, Xu SY, Bian G, Liu K, Chang TR, Lin H, Lu ZY, Wang Z, Jia S, Wang W, Hasan MZ. Giant and anisotropic many-body spin–orbit tunability in a strongly correlated kagome magnet. Nature 2018; 562:91-95. [DOI: 10.1038/s41586-018-0502-7] [Citation(s) in RCA: 176] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 11/09/2022]
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34
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Singh B, Chang G, Chang TR, Huang SM, Su C, Lin MC, Lin H, Bansil A. Tunable double-Weyl Fermion semimetal state in the SrSi 2 materials class. Sci Rep 2018; 8:10540. [PMID: 30002388 PMCID: PMC6043586 DOI: 10.1038/s41598-018-28644-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/20/2018] [Indexed: 11/13/2022] Open
Abstract
We discuss first-principles topological electronic structure of noncentrosymmetric SrSi2 materials class based on the hybrid exchange-correlation functional. Topological phase diagram of SrSi2 is mapped out as a function of the lattice constant with focus on the semimetal order. A tunable double-Weyl Fermion state in Sr1-xCaxSi2 and Sr1-xBaxSi2 alloys is identified. Ca doping in SrSi2 is shown to yield a double-Weyl semimetal with a large Fermi arc length, while Ba doping leads to a transition from the topological semimetal to a gapped insulator state. Our study indicates that SrSi2 materials family could provide an interesting platform for accessing the unique topological properties of Weyl semimetals.
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Affiliation(s)
- Bahadur Singh
- SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D Materials Information Functional Devices and Systems of Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, ShenZhen, 518060, China
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, Singapore, 117546, Singapore
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Chenliang Su
- SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D Materials Information Functional Devices and Systems of Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, ShenZhen, 518060, China.
| | - Ming-Chieh Lin
- Multidisciplinary Computational Laboratory, Department of Electrical and Biomedical Engineering, Hanyang University, Seoul, 04763, South Korea.
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore.
- Department of Physics, National University of Singapore, Singapore, 117546, Singapore.
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan.
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts, 02115, USA
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35
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Chang G, Xu SY, Wieder BJ, Sanchez DS, Huang SM, Belopolski I, Chang TR, Zhang S, Bansil A, Lin H, Hasan MZ. Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi. Phys Rev Lett 2017; 119:206401. [PMID: 29219365 DOI: 10.1103/physrevlett.119.206401] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Indexed: 05/02/2023]
Abstract
The theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. In particular, the Fermi surfaces of chiral semimetals carry quantized Chern numbers, making them an attractive platform for the observation of exotic transport and optical phenomena. While the simplest example of a chiral fermion in condensed matter is a conventional |C|=1 Weyl fermion, recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. In this Letter, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a filling-enforced semimetal that features near its Fermi surface a chiral double sixfold-degenerate spin-1 Weyl node at R and a previously uncharacterized fourfold-degenerate chiral fermion at Γ. Each unconventional fermion displays Chern number ±4 at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.
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Affiliation(s)
- Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Benjamin J Wieder
- Nordita, Center for Quantum Materials, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Songtian Zhang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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36
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Zheng H, Chang G, Huang SM, Guo C, Zhang X, Zhang S, Yin J, Xu SY, Belopolski I, Alidoust N, Sanchez DS, Bian G, Chang TR, Neupert T, Jeng HT, Jia S, Lin H, Hasan MZ. Mirror Protected Dirac Fermions on a Weyl Semimetal NbP Surface. Phys Rev Lett 2017; 119:196403. [PMID: 29219493 DOI: 10.1103/physrevlett.119.196403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 06/07/2023]
Abstract
The first Weyl semimetal was recently discovered in the NbP class of compounds. Although the topology of these novel materials has been identified, the surface properties are not yet fully understood. By means of scanning tunneling spectroscopy, we find that NbP's (001) surface hosts a pair of Dirac cones protected by mirror symmetry. Through our high-resolution spectroscopic measurements, we resolve the quantum interference patterns arising from these novel Dirac fermions and reveal their electronic structure, including the linear dispersions. Our data, in agreement with our theoretical calculations, uncover further interesting features of the Weyl semimetal NbP's already exotic surface. Moreover, we discuss the similarities and distinctions between the Dirac fermions here and those in topological crystalline insulators in terms of symmetry protection and topology.
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Affiliation(s)
- Hao Zheng
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Cheng Guo
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiao Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Songtian Zhang
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Jiaxin Yin
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Su-Yang Xu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ilya Belopolski
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Nasser Alidoust
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Daniel S Sanchez
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Guang Bian
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Titus Neupert
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - M Zahid Hasan
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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37
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Belopolski I, Yu P, Sanchez DS, Ishida Y, Chang TR, Zhang SS, Xu SY, Zheng H, Chang G, Bian G, Jeng HT, Kondo T, Lin H, Liu Z, Shin S, Hasan MZ. Signatures of a time-reversal symmetric Weyl semimetal with only four Weyl points. Nat Commun 2017; 8:942. [PMID: 29038436 PMCID: PMC5752680 DOI: 10.1038/s41467-017-00938-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 08/04/2017] [Indexed: 11/09/2022] Open
Abstract
Through intense research on Weyl semimetals during the past few years, we have come to appreciate that typical Weyl semimetals host many Weyl points. Nonetheless, the minimum nonzero number of Weyl points allowed in a time-reversal invariant Weyl semimetal is four. Realizing such a system is of fundamental interest and may simplify transport experiments. Recently, it was predicted that TaIrTe4 realizes a minimal Weyl semimetal. However, the Weyl points and Fermi arcs live entirely above the Fermi level, making them inaccessible to conventional angle-resolved photoemission spectroscopy (ARPES). Here, we use pump-probe ARPES to directly access the band structure above the Fermi level in TaIrTe4. We observe signatures of Weyl points and topological Fermi arcs. Combined with ab initio calculation, our results show that TaIrTe4 is a Weyl semimetal with the minimum number of four Weyl points. Our work provides a simpler platform for accessing exotic transport phenomena arising in Weyl semimetals.Weyl semimetals are interesting because they are characterized by topological invariants, but specific examples discovered to date tend to have complicated band structures with many Weyl points. Here, the authors show that TaIrTe4 has only four Weyl points, the minimal number required by time-reversal symmetry.
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Affiliation(s)
- Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
| | - Peng Yu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Yukiaki Ishida
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba, 277-8581, Japan
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan.,Department of Physics, National Cheng Kung University, Tainan, 701, Taiwan
| | - Songtian S Zhang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Hao Zheng
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Guang Bian
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA.,Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan.,Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Takeshi Kondo
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba, 277-8581, Japan
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Zheng Liu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.,NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore.,CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore, 637553, Singapore
| | - Shik Shin
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba, 277-8581, Japan
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, 08544, USA. .,Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA.
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38
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Hsu WT, Lu LS, Wang D, Huang JK, Li MY, Chang TR, Chou YC, Juang ZY, Jeng HT, Li LJ, Chang WH. Evidence of indirect gap in monolayer WSe 2. Nat Commun 2017; 8:929. [PMID: 29030548 PMCID: PMC5640683 DOI: 10.1038/s41467-017-01012-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/11/2017] [Indexed: 11/18/2022] Open
Abstract
Monolayer transition metal dichalcogenides, such as MoS2 and WSe2, have been known as direct gap semiconductors and emerged as new optically active materials for novel device applications. Here we reexamine their direct gap properties by investigating the strain effects on the photoluminescence of monolayer MoS2 and WSe2. Instead of applying stress, we investigate the strain effects by imaging the direct exciton populations in monolayer WSe2-MoS2 and MoSe2-WSe2 lateral heterojunctions with inherent strain inhomogeneity. We find that unstrained monolayer WSe2 is actually an indirect gap material, as manifested in the observed photoluminescence intensity-energy correlation, from which the difference between the direct and indirect optical gaps can be extracted by analyzing the exciton thermal populations. Our findings combined with the estimated exciton binding energy further indicate that monolayer WSe2 exhibits an indirect quasiparticle gap, which has to be reconsidered in further studies for its fundamental properties and device applications.Monolayer transition metal dichalcogenides have so far been thought to be direct bandgap semiconductors. Here, the authors revisit this assumption and find that unstrained monolayer WSe2 is an indirect-gap material, as evidenced by the observed photoluminescence intensity-energy correlation.
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Affiliation(s)
- Wei-Ting Hsu
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Li-Syuan Lu
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Dean Wang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Jing-Kai Huang
- Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Ming-Yang Li
- Research Center for Applied Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yi-Chia Chou
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Zhen-Yu Juang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Lain-Jong Li
- Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Wen-Hao Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan.
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39
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Kim H, Yoshida Y, Lee CC, Chang TR, Jeng HT, Lin H, Haga Y, Fisk Z, Hasegawa Y. Atomic-scale visualization of surface-assisted orbital order. Sci Adv 2017; 3:eaao0362. [PMID: 28948229 PMCID: PMC5609848 DOI: 10.1126/sciadv.aao0362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/01/2017] [Indexed: 05/31/2023]
Abstract
Orbital-related physics attracts growing interest in condensed matter research, but direct real-space access of the orbital degree of freedom is challenging. We report a first, real-space, imaging of a surface-assisted orbital ordered structure on a cobalt-terminated surface of the well-studied heavy fermion compound CeCoIn5. Within small tip-sample distances, the cobalt atoms on a cleaved (001) surface take on dumbbell shapes alternatingly aligned in the [100] and [010] directions in scanning tunneling microscopy topographies. First-principles calculations reveal that this structure is a consequence of the staggered d xz -d yz orbital order triggered by enhanced on-site Coulomb interaction at the surface. This so far overlooked surface-assisted orbital ordering may prevail in transition metal oxides, heavy fermion superconductors, and other materials.
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Affiliation(s)
- Howon Kim
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Yasuo Yoshida
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Chi-Cheng Lee
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Yoshinori Haga
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
| | - Zachary Fisk
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
- Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA
| | - Yukio Hasegawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
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40
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Okada Y, Shiau SY, Chang TR, Chang G, Kobayashi M, Shimizu R, Jeng HT, Shiraki S, Kumigashira H, Bansil A, Lin H, Hitosugi T. Quasiparticle Interference on Cubic Perovskite Oxide Surfaces. Phys Rev Lett 2017; 119:086801. [PMID: 28952762 DOI: 10.1103/physrevlett.119.086801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Indexed: 06/07/2023]
Abstract
We report the observation of coherent surface states on cubic perovskite oxide SrVO_{3}(001) thin films through spectroscopic-imaging scanning tunneling microscopy. A direct link between the observed quasiparticle interference patterns and the formation of a d_{xy}-derived surface state is supported by first-principles calculations. We show that the apical oxygens on the topmost VO_{2} plane play a critical role in controlling the coherent surface state via modulating orbital state.
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Affiliation(s)
- Yoshinori Okada
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Shiue-Yuan Shiau
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Masaki Kobayashi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Ryota Shimizu
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Susumu Shiraki
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Hiroshi Kumigashira
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Taro Hitosugi
- Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
- Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo 152-8552, Japan
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41
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Gui X, Chang TR, Kong T, Pan MT, Cava RJ, Xie W. Monoclinic 122-Type BaIr₂Ge₂ with a Channel Framework: A Structural Connection between Clathrate and Layered Compounds. Materials (Basel) 2017; 10:ma10070818. [PMID: 28773175 PMCID: PMC5551861 DOI: 10.3390/ma10070818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 11/16/2022]
Abstract
A new 122-type phase, monoclinic BaIr₂Ge₂ is successfully synthesized by arc melting; X-ray diffraction and scanning electron microscopy are used to purify the phase and determine its crystal structure. BaIr₂Ge₂ adopts a clathrate-like channel framework structure of the monoclinic BaRh₂Si₂-type, with space group P2₁/c. Structural comparisons of clathrate, ThCr₂Si₂, CaBe₂Ge₂, and BaRh₂Si2 structure types indicate that BaIr₂Ge₂ can be considered as an intermediate between clathrate and layered compounds. Magnetic measurements show it to be diamagnetic and non-superconducting down to 1.8 K. Different from many layered or clathrate compounds, monoclinic BaIr₂Ge₂ displays a metallic resistivity. Electronic structure calculations performed for BaIr₂Ge₂ support its observed structural stability and physical properties.
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Affiliation(s)
- Xin Gui
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
| | - Tai Kong
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA.
| | - Max T Pan
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA.
| | - Weiwei Xie
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
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42
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Chang TR, Xu SY, Sanchez DS, Tsai WF, Huang SM, Chang G, Hsu CH, Bian G, Belopolski I, Yu ZM, Yang SA, Neupert T, Jeng HT, Lin H, Hasan MZ. Type-II Symmetry-Protected Topological Dirac Semimetals. Phys Rev Lett 2017; 119:026404. [PMID: 28753359 DOI: 10.1103/physrevlett.119.026404] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 06/07/2023]
Abstract
The recent proposal of the type-II Weyl semimetal state has attracted significant interest. In this Letter, we propose the concept of the three-dimensional type-II Dirac fermion and theoretically identify this new symmetry-protected topological state in the large family of transition-metal icosagenides, MA_{3} (M=V, Nb, Ta; A=Al, Ga, In). We show that the VAl_{3} family features a pair of strongly Lorentz-violating type-II Dirac nodes and that each Dirac node can be split into four type-II Weyl nodes with chiral charge ±1 via symmetry breaking. Furthermore, we predict that the Landau level spectrum arising from the type-II Dirac fermions in VAl_{3} is distinct from that of known Dirac or Weyl semimetals. We also demonstrate a topological phase transition from a type-II Dirac semimetal to a quadratic Weyl semimetal or a topological crystalline insulator via crystalline distortions.
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Affiliation(s)
- Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Wei-Feng Tsai
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, 117546 Singapore, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Singapore
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, 117546 Singapore, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Singapore
| | - Chuang-Han Hsu
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, 117546 Singapore, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Singapore
| | - Guang Bian
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Zhi-Ming Yu
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Titus Neupert
- Department of Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, 117546 Singapore, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Singapore
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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43
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Xu SY, Alidoust N, Chang G, Lu H, Singh B, Belopolski I, Sanchez DS, Zhang X, Bian G, Zheng H, Husanu MA, Bian Y, Huang SM, Hsu CH, Chang TR, Jeng HT, Bansil A, Neupert T, Strocov VN, Lin H, Jia S, Hasan MZ. Discovery of Lorentz-violating type II Weyl fermions in LaAlGe. Sci Adv 2017; 3:e1603266. [PMID: 28630919 PMCID: PMC5457030 DOI: 10.1126/sciadv.1603266] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/07/2017] [Indexed: 05/17/2023]
Abstract
In quantum field theory, Weyl fermions are relativistic particles that travel at the speed of light and strictly obey the celebrated Lorentz symmetry. Their low-energy condensed matter analogs are Weyl semimetals, which are conductors whose electronic excitations mimic the Weyl fermion equation of motion. Although the traditional (type I) emergent Weyl fermions observed in TaAs still approximately respect Lorentz symmetry, recently, the so-called type II Weyl semimetal has been proposed, where the emergent Weyl quasiparticles break the Lorentz symmetry so strongly that they cannot be smoothly connected to Lorentz symmetric Weyl particles. Despite some evidence of nontrivial surface states, the direct observation of the type II bulk Weyl fermions remains elusive. We present the direct observation of the type II Weyl fermions in crystalline solid lanthanum aluminum germanide (LaAlGe) based on our photoemission data alone, without reliance on band structure calculations. Moreover, our systematic data agree with the theoretical calculations, providing further support on our experimental results.
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Affiliation(s)
- Su-Yang Xu
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
| | - Nasser Alidoust
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
- Rigetti & Co Inc., 775 Heinz Avenue, Berkeley, CA 94710, USA
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Hong Lu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Bahadur Singh
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Ilya Belopolski
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
| | - Daniel S. Sanchez
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
| | - Xiao Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Guang Bian
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Hao Zheng
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
| | - Marious-Adrian Husanu
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
- National Institute of Materials Physics, 405A Atomistilor Street, 077125 Magurele, Romania
| | - Yi Bian
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
| | - Shin-Ming Huang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
- Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Chuang-Han Hsu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Titus Neupert
- Department of Physics, University of Zurich, Winterthurerstrasse 190, CH-8052, Switzerland
| | - Vladimir N. Strocov
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - M. Zahid Hasan
- Department of Physics, Laboratory for Topological Quantum Matter and Spectroscopy (B7), Princeton University, Princeton, NJ 08544, USA
- Corresponding author.
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44
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Chang G, Xu SY, Huang SM, Sanchez DS, Hsu CH, Bian G, Yu ZM, Belopolski I, Alidoust N, Zheng H, Chang TR, Jeng HT, Yang SA, Neupert T, Lin H, Hasan MZ. Nexus fermions in topological symmorphic crystalline metals. Sci Rep 2017; 7:1688. [PMID: 28490762 PMCID: PMC5431971 DOI: 10.1038/s41598-017-01523-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 02/17/2017] [Indexed: 11/09/2022] Open
Abstract
Topological metals and semimetals (TMs) have recently drawn significant interest. These materials give rise to condensed matter realizations of many important concepts in high-energy physics, leading to wide-ranging protected properties in transport and spectroscopic experiments. It has been well-established that the known TMs can be classified by the dimensionality of the topologically protected band degeneracies. While Weyl and Dirac semimetals feature zero-dimensional points, the band crossing of nodal-line semimetals forms a one-dimensional closed loop. In this paper, we identify a TM that goes beyond the above paradigms. It shows an exotic configuration of degeneracies without a well-defined dimensionality. Specifically, it consists of 0D nexus with triple-degeneracy that interconnects 1D lines with double-degeneracy. We show that, because of the novel form of band crossing, the new TM cannot be described by the established results that characterize the topology of the Dirac and Weyl nodes. Moreover, triply-degenerate nodes realize emergent fermionic quasiparticles not present in relativistic quantum field theory. We present materials candidates. Our results open the door for realizing new topological phenomena and fermions including transport anomalies and spectroscopic responses in metallic crystals with nontrivial topology beyond the Weyl/Dirac paradigm.
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Affiliation(s)
- Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA.
| | - Shin-Ming Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Chuang-Han Hsu
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Guang Bian
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Zhi-Ming Yu
- School of Physics, Beijing Institute of Technology, Beijing, 100081, China.,Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Nasser Alidoust
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Hao Zheng
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan.,Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Titus Neupert
- Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey, 08544, USA.,Department of Physics, University of Zurich, Winterthurerstrass, 190, CH-8052, Switzerland
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore. .,Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore.
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey, 08544, USA.
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45
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Trainer DJ, Putilov AV, Di Giorgio C, Saari T, Wang B, Wolak M, Chandrasena RU, Lane C, Chang TR, Jeng HT, Lin H, Kronast F, Gray AX, Xi X, Nieminen J, Bansil A, Iavarone M. Erratum: Inter-Layer Coupling Induced Valence Band Edge Shift in Mono- to Few-Layer MoS 2. Sci Rep 2017; 7:42619. [PMID: 28290442 PMCID: PMC5349580 DOI: 10.1038/srep42619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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46
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Sankar R, Rao GN, Muthuselvam IP, Chang TR, Jeng HT, Murugan GS, Lee WL, Chou FC. Anisotropic superconducting property studies of single crystal PbTaSe 2. J Phys Condens Matter 2017; 29:095601. [PMID: 28098075 DOI: 10.1088/1361-648x/aa4edb] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The anisotropic superconducting properties of PbTaSe2 single crystal is reported. Superconductivity with T c = 3.83 ± 0.02 K has been characterized fully with electrical resistivity ρ(T), magnetic susceptibility χ(T), and specific heat C p (T) measurements using single crystal samples. The superconductivity is type-II with lower critical field H c1 and upper critical field H c2 of 65 and 450 Oe (H⊥ to the ab-plane), 140 and 1500 Oe (H|| to the ab-plane), respectively. These results indicate that the superconductivity of PbTaSe2 is anisotropic. The superconducting anisotropy, electron-phonon coupling λ ep, superconducting energy gap Δ0, and the specific heat jump ΔC/γT c at T c confirms that PbTaSe2 can be categorized as a bulk superconductor.
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Affiliation(s)
- Raman Sankar
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan. Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
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47
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Trainer DJ, Putilov AV, Di Giorgio C, Saari T, Wang B, Wolak M, Chandrasena RU, Lane C, Chang TR, Jeng HT, Lin H, Kronast F, Gray AX, Xi XX, Nieminen J, Bansil A, Iavarone M. Inter-Layer Coupling Induced Valence Band Edge Shift in Mono- to Few-Layer MoS 2. Sci Rep 2017; 7:40559. [PMID: 28084465 PMCID: PMC5233980 DOI: 10.1038/srep40559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/08/2016] [Indexed: 12/04/2022] Open
Abstract
Recent progress in the synthesis of monolayer MoS2, a two-dimensional direct band-gap semiconductor, is paving new pathways toward atomically thin electronics. Despite the large amount of literature, fundamental gaps remain in understanding electronic properties at the nanoscale. Here, we report a study of highly crystalline islands of MoS2 grown via a refined chemical vapor deposition synthesis technique. Using high resolution scanning tunneling microscopy and spectroscopy (STM/STS), photoemission electron microscopy/spectroscopy (PEEM) and μ-ARPES we investigate the electronic properties of MoS2 as a function of the number of layers at the nanoscale and show in-depth how the band gap is affected by a shift of the valence band edge as a function of the layer number. Green's function based electronic structure calculations were carried out in order to shed light on the mechanism underlying the observed bandgap reduction with increasing thickness, and the role of the interfacial Sulphur atoms is clarified. Our study, which gives new insight into the variation of electronic properties of MoS2 films with thickness bears directly on junction properties of MoS2, and thus impacts electronics application of MoS2.
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Affiliation(s)
| | | | | | - Timo Saari
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Baokai Wang
- Physics Department, Northeastern University, Boston MA 02115, USA
| | - Mattheus Wolak
- Physics Department, Temple University, Philadelphia PA 19122, USA
| | | | - Christopher Lane
- Physics Department, Northeastern University, Boston MA 02115, USA
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 117546 Singapore
- Department of Physics, National University of Singapore, 117546 Singapore
| | - Florian Kronast
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Straße 15, 12489 Berlin, Germany
| | | | - Xiaoxing X. Xi
- Physics Department, Temple University, Philadelphia PA 19122, USA
| | - Jouko Nieminen
- Department of Physics, Tampere University of Technology, Tampere, Finland
- Physics Department, Northeastern University, Boston MA 02115, USA
| | - Arun Bansil
- Physics Department, Northeastern University, Boston MA 02115, USA
| | - Maria Iavarone
- Physics Department, Temple University, Philadelphia PA 19122, USA
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48
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Yu P, Lin J, Sun L, Le QL, Yu X, Gao G, Hsu CH, Wu D, Chang TR, Zeng Q, Liu F, Wang QJ, Jeng HT, Lin H, Trampert A, Shen Z, Suenaga K, Liu Z. Metal-Semiconductor Phase-Transition in WSe 2(1-x) Te 2x Monolayer. Adv Mater 2017; 29:1603991. [PMID: 27874223 DOI: 10.1002/adma.201603991] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/12/2016] [Indexed: 06/06/2023]
Abstract
A metal-semiconductor phase transition in a ternary transition metal dichalcogenide (TMD) monolayer is achieved by alloying Te into WSe2 (WSe2(1-x) Te2x , where x = 0%-100%). The optical bandgaps of the WSe2(1-x) Te2x monolayer can be tuned from 1.67 to 1.44 eV (2H semiconductor) and drops to 0 eV (1Td metal), which opens up an exciting opportunity in functional electronic/optoelectronic devices.
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Affiliation(s)
- Peng Yu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Junhao Lin
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Linfeng Sun
- School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Quang Luan Le
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xuechao Yu
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Guanhui Gao
- Paul-Drude-Institut für Festkörperelektronik Leibniz-Institut im Forschungsverbund Berlin Hausvogteiplatz 5-7, 10117, Berlin, Germany
| | - Chuang-Han Hsu
- Department of Physics, National University of Singapore, 117542, Singapore
| | - Di Wu
- Department of Physics, National University of Singapore, 117542, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Qingsheng Zeng
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Fucai Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Qi Jie Wang
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin Lin
- Department of Physics, National University of Singapore, 117542, Singapore
| | - Achim Trampert
- Paul-Drude-Institut für Festkörperelektronik Leibniz-Institut im Forschungsverbund Berlin Hausvogteiplatz 5-7, 10117, Berlin, Germany
| | - Zexiang Shen
- School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Kazu Suenaga
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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49
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Zhou J, Liu F, Lin J, Huang X, Xia J, Zhang B, Zeng Q, Wang H, Zhu C, Niu L, Wang X, Fu W, Yu P, Chang TR, Hsu CH, Wu D, Jeng HT, Huang Y, Lin H, Shen Z, Yang C, Lu L, Suenaga K, Zhou W, Pantelides ST, Liu G, Liu Z. Large-Area and High-Quality 2D Transition Metal Telluride. Adv Mater 2017; 29. [PMID: 27859781 DOI: 10.1002/adma.201603471] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/19/2016] [Indexed: 05/17/2023]
Abstract
Large-area and high-quality 2D transition metal tellurides are synthesized by the chemical vapor deposition method. The as-grown WTe2 maintains two different stacking sequences in the bilayer, where the atomic structure of the stacking boundary is revealed by scanning transmission electron microscopy. The low-temperature transport measurements reveal a novel semimetal-to-insulator transition in WTe2 layers and an enhanced superconductivity in few-layer MoTe2 .
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Affiliation(s)
- Jiadong Zhou
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Fucai Liu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Junhao Lin
- Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN, 37831, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Xiangwei Huang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Juan Xia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Bowei Zhang
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Qingsheng Zeng
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Hong Wang
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Chao Zhu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Lin Niu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Xuewen Wang
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Wei Fu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Peng Yu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Chuang-Han Hsu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Di Wu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Yizhong Huang
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Zexiang Shen
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Changli Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Li Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Kazu Suenaga
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Wu Zhou
- Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN, 37831, USA
| | - Sokrates T Pantelides
- Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN, 37831, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA
| | - Guangtong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zheng Liu
- Centre for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Centre for Micro-/Nano-electronics (NOVITAS), School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore, 637553, Singapore
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50
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Zheng H, Bian G, Chang G, Lu H, Xu SY, Wang G, Chang TR, Zhang S, Belopolski I, Alidoust N, Sanchez DS, Song F, Jeng HT, Yao N, Bansil A, Jia S, Lin H, Hasan MZ. Atomic-Scale Visualization of Quasiparticle Interference on a Type-II Weyl Semimetal Surface. Phys Rev Lett 2016; 117:266804. [PMID: 28059545 DOI: 10.1103/physrevlett.117.266804] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Indexed: 06/06/2023]
Abstract
We combine quasiparticle interference simulation (theory) and atomic resolution scanning tunneling spectromicroscopy (experiment) to visualize the interference patterns on a type-II Weyl semimetal Mo_{x}W_{1-x}Te_{2} for the first time. Our simulation based on first-principles band topology theoretically reveals the surface electron scattering behavior. We identify the topological Fermi arc states and reveal the scattering properties of the surface states in Mo_{0.66}W_{0.34}Te_{2}. In addition, our result reveals an experimental signature of the topology via the interconnectivity of bulk and surface states, which is essential for understanding the unusual nature of this material.
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Affiliation(s)
- Hao Zheng
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Guang Bian
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Guoqing Chang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - Hong Lu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Su-Yang Xu
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Guangqiang Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Tay-Rong Chang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Songtian Zhang
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Ilya Belopolski
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Nasser Alidoust
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Daniel S Sanchez
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Nan Yao
- Princeton Institute for the Science and Technology of Materials, Princeton University, 70 Prospect Avenue, Princeton, New Jersey 08540, USA
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Hsin Lin
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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