1
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Teng X, Tam DW, Chen L, Tan H, Xie Y, Gao B, Granroth GE, Ivanov A, Bourges P, Yan B, Yi M, Dai P. Spin-Charge-Lattice Coupling across the Charge Density Wave Transition in a Kagome Lattice Antiferromagnet. PHYSICAL REVIEW LETTERS 2024; 133:046502. [PMID: 39121411 DOI: 10.1103/physrevlett.133.046502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/25/2024] [Indexed: 08/11/2024]
Abstract
Understanding spin and lattice excitations in a metallic magnetic ordered system forms the basis to unveil the magnetic and lattice exchange couplings and their interactions with itinerant electrons. Kagome lattice antiferromagnet FeGe is interesting because it displays a rare charge density wave (CDW) deep inside the antiferromagnetic ordered phase that interacts with the magnetic order. We use neutron scattering to study the evolution of spin and lattice excitations across the CDW transition T_{CDW} in FeGe. While spin excitations below ∼100 meV can be well described by spin waves of a spin-1 Heisenberg Hamiltonian, spin excitations at higher energies are centered around the Brillouin zone boundary and extend up to ∼180 meV consistent with quasiparticle excitations across spin-polarized electron-hole Fermi surfaces. Furthermore, c-axis spin wave dispersion and Fe-Ge optical phonon modes show a clear hardening below T_{CDW} due to spin-charge-lattice coupling but with no evidence of a phonon Kohn anomaly. By comparing our experimental results with density functional theory calculations in absolute units, we conclude that FeGe is a Hund's metal in the intermediate correlated regime where magnetism has contributions from both itinerant and localized electrons arising from spin polarized electronic bands near the Fermi level.
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2
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Chen Z, Wu X, Zhou S, Zhang J, Yin R, Li Y, Li M, Gong J, He M, Chai Y, Zhou X, Wang Y, Wang A, Yan YJ, Feng DL. Discovery of a long-ranged charge order with 1/4 Ge1-dimerization in an antiferromagnetic Kagome metal. Nat Commun 2024; 15:6262. [PMID: 39048561 PMCID: PMC11269715 DOI: 10.1038/s41467-024-50661-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 07/10/2024] [Indexed: 07/27/2024] Open
Abstract
Exotic quantum states arise from the interplay of various degrees of freedom such as charge, spin, orbital, and lattice. Recently, a short-ranged charge order (CO) was discovered deep inside the antiferromagnetic phase of Kagome magnet FeGe, exhibiting close relationships with magnetism. Despite extensive investigations, the CO mechanism remains controversial, mainly because the short-ranged behavior hinders precise identification of CO superstructure. Here, combining multiple experimental techniques, we report the observation of a long-ranged CO in high-quality FeGe samples, which is accompanied with a first-order structural transition. With these high-quality samples, the distorted 2 × 2 × 2 CO superstructure is characterized by a strong dimerization along the c-axis of 1/4 of Ge1-sites in Fe3Ge layers, and in response to that, the 2 × 2 in-plane charge modulations are induced. Moreover, we show that the previously reported short-ranged CO might be related to large occupational disorders at Ge1-site, which upsets the equilibrium of the CO state and the ideal 1 × 1 × 1 structure with very close energies, inducing nanoscale coexistence of these two phases. Our study provides important clues for further understanding the CO properties in FeGe and helps to identify the CO mechanism.
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Affiliation(s)
- Ziyuan Chen
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Xueliang Wu
- Low temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - Shiming Zhou
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Jiakang Zhang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Ruotong Yin
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Yuanji Li
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Mingzhe Li
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Jiashuo Gong
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
| | - Mingquan He
- Low temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - Yisheng Chai
- Low temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - Xiaoyuan Zhou
- Low temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - Yilin Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China
- National Synchrotron Radiation Laboratory School of Nuclear Science and Technology, and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China
| | - Aifeng Wang
- Low temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China.
| | - Ya-Jun Yan
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
| | - Dong-Lai Feng
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, China.
- National Synchrotron Radiation Laboratory School of Nuclear Science and Technology, and New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, China.
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3
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Xing Y, Bae S, Ritz E, Yang F, Birol T, Capa Salinas AN, Ortiz BR, Wilson SD, Wang Z, Fernandes RM, Madhavan V. Optical manipulation of the charge-density-wave state in RbV 3Sb 5. Nature 2024; 631:60-66. [PMID: 38867046 DOI: 10.1038/s41586-024-07519-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 05/03/2024] [Indexed: 06/14/2024]
Abstract
Broken time-reversal symmetry in the absence of spin order indicates the presence of unusual phases such as orbital magnetism and loop currents1-4. The recently discovered kagome superconductors AV3Sb5 (where A is K, Rb or Cs)5,6 display an exotic charge-density-wave (CDW) state and have emerged as a strong candidate for materials hosting a loop current phase. The idea that the CDW breaks time-reversal symmetry7-14 is, however, being intensely debated due to conflicting experimental data15-17. Here we use laser-coupled scanning tunnelling microscopy to study RbV3Sb5. By applying linearly polarized light along high-symmetry directions, we show that the relative intensities of the CDW peaks can be reversibly switched, implying a substantial electro-striction response, indicative of strong nonlinear electron-phonon coupling. A similar CDW intensity switching is observed with perpendicular magnetic fields, which implies an unusual piezo-magnetic response that, in turn, requires time-reversal symmetry breaking. We show that the simplest CDW that satisfies these constraints is an out-of-phase combination of bond charge order and loop currents that we dub a congruent CDW flux phase. Our laser scanning tunnelling microscopy data open the door to the possibility of dynamic optical control of complex quantum phenomenon in correlated materials.
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Affiliation(s)
- Yuqing Xing
- Department of Physics and Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Seokjin Bae
- Department of Physics and Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Ethan Ritz
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Fan Yang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Turan Birol
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA
| | - Andrea N Capa Salinas
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Brenden R Ortiz
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Stephen D Wilson
- Materials Department, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Rafael M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Vidya Madhavan
- Department of Physics and Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA.
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4
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Wenzel M, Uykur E, Tsirlin AA, Pal S, Roy RM, Yi C, Shekhar C, Felser C, Pronin AV, Dressel M. Intriguing Low-Temperature Phase in the Antiferromagnetic Kagome Metal FeGe. PHYSICAL REVIEW LETTERS 2024; 132:266505. [PMID: 38996298 DOI: 10.1103/physrevlett.132.266505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/24/2024] [Indexed: 07/14/2024]
Abstract
The properties of kagome metals are governed by the interdependence of band topology and electronic correlations resulting in remarkably rich phase diagrams. Here, we study the temperature evolution of the bulk electronic structure of the antiferromagnetic kagome metal FeGe using infrared spectroscopy. We uncover drastic changes in the low-energy interband absorption at the 100 K structural phase transition that has been linked to a charge-density-wave (CDW) instability. We explain this effect by the minuscule Fe displacement in the kagome plane, which results in parallel bands in the vicinity of the Fermi level. In contrast to conventional CDW materials, however, the spectral weight shifts to low energies, ruling out the opening of a CDW gap in FeGe.
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5
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Wu X, Mi X, Zhang L, Wang CW, Maraytta N, Zhou X, He M, Merz M, Chai Y, Wang A. Annealing-Tunable Charge Density Wave in the Magnetic Kagome Material FeGe. PHYSICAL REVIEW LETTERS 2024; 132:256501. [PMID: 38996264 DOI: 10.1103/physrevlett.132.256501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/13/2024] [Accepted: 05/06/2024] [Indexed: 07/14/2024]
Abstract
The unprecedented phenomenon that a charge density wave (CDW) emerges inside the antiferromagnetic (AFM) phase indicates an unusual CDW mechanism associated with magnetism in FeGe. Here, we demonstrate that both the CDW and magnetism of FeGe can be effectively tuned through postgrowth annealing treatments. Instead of the short-range CDW reported earlier, a long-range CDW order is realized below 110 K in single crystals annealed at 320 °C for over 48 h. The CDW and AFM transition temperatures appear to be inversely correlated with each other. The onset of the CDW phase significantly reduces the critical field of the spin-flop transition, whereas the CDW transition remains stable against minor variations in magnetic orders such as annealing-induced magnetic clusters and spin-canting transitions. Single-crystal x-ray diffraction measurements reveal substantial disorder on the Ge1 site, which is characterized by displacement of the Ge1 atom from the Fe_{3}Ge layer along the c axis and can be reversibly modified by the annealing process. The observed annealing-tunable CDW and magnetic orders can be well understood in terms of disorder on the Ge1 site. Our study provides a vital starting point for the exploration of the unconventional CDW mechanism in FeGe and of kagome materials in general.
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Affiliation(s)
- Xueliang Wu
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | - Xinrun Mi
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | - Long Zhang
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | | | | | | | - Mingquan He
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | | | | | - Aifeng Wang
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
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6
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Chen L, Xie F, Sur S, Hu H, Paschen S, Cano J, Si Q. Emergent flat band and topological Kondo semimetal driven by orbital-selective correlations. Nat Commun 2024; 15:5242. [PMID: 38898039 PMCID: PMC11186837 DOI: 10.1038/s41467-024-49306-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Flat electronic bands are expected to show proportionally enhanced electron correlations, which may generate a plethora of novel quantum phases and unusual low-energy excitations. They are increasingly being pursued in d-electron-based systems with crystalline lattices that feature destructive electronic interference, where they are often topological. Such flat bands, though, are generically located far away from the Fermi energy, which limits their capacity to partake in the low-energy physics. Here we show that electron correlations produce emergent flat bands that are pinned to the Fermi energy. We demonstrate this effect within a Hubbard model, in the regime described by Wannier orbitals where an effective Kondo description arises through orbital-selective Mott correlations. Moreover, the correlation effect cooperates with symmetry constraints to produce a topological Kondo semimetal. Our results motivate a novel design principle for Weyl Kondo semimetals in a new setting, viz. d-electron-based materials on suitable crystal lattices, and uncover interconnections among seemingly disparate systems that may inspire fresh understandings and realizations of correlated topological effects in quantum materials and beyond.
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Affiliation(s)
- Lei Chen
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Fang Xie
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Shouvik Sur
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Haoyu Hu
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
- Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018, Donostia-San Sebastian, Spain
| | - Silke Paschen
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040, Vienna, Austria
| | - Jennifer Cano
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, 10010, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA.
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7
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Wang W, Zhou G, Lin W, Feng Z, Wang Y, Liang M, Zhang Z, Wu M, Liu L, Watanabe K, Taniguchi T, Yang W, Zhang G, Liu K, Gao J, Liu Y, Xie XC, Song Z, Lu X. Correlated Charge Density Wave Insulators in Chirally Twisted Triple Bilayer Graphene. PHYSICAL REVIEW LETTERS 2024; 132:246501. [PMID: 38949356 DOI: 10.1103/physrevlett.132.246501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/07/2024] [Indexed: 07/02/2024]
Abstract
Electrons residing in a flat-band system can play a vital role in triggering spectacular phenomenology due to relatively large interactions and spontaneous breaking of different degeneracies. In this work, we demonstrate chirally twisted triple bilayer graphene, a new moiré structure formed by three pieces of helically stacked Bernal bilayer graphene, as a highly tunable flat-band system. In addition to the correlated insulators showing at integer moiré fillings, commonly attributed to interaction induced symmetry broken isospin flavors in graphene, we observe abundant insulating states at half-integer moiré fillings, suggesting a longer-range interaction and the formation of charge density wave insulators which spontaneously break the moiré translation symmetry. With weak out-of-plane magnetic field applied, as observed half-integer filling states are enhanced and more quarter-integer filling states appear, pointing toward further quadrupling moiré unit cells. The insulating states at fractional fillings combined with Hartree-Fock calculations demonstrate the observation of a new type of correlated charge density wave insulators in graphene and points to a new accessible twist manner engineering correlated moiré electronics.
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Affiliation(s)
| | | | | | - Zuo Feng
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Centre for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
| | | | | | | | | | | | | | | | | | | | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Centre for Nano-optoelectronics, School of Physics, Peking University, 100871, Beijing, China
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8
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Du H, Zheng Y, Pei C, Yim CM, Qi Y, Zhong R. Crystal structure, properties and pressure-induced insulator-metal transition in layered kagome chalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:365702. [PMID: 38821103 DOI: 10.1088/1361-648x/ad52e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 05/31/2024] [Indexed: 06/02/2024]
Abstract
Layered materials with kagome lattice have attracted a lot of attention due to the presence of nontrivial topological bands and correlated electronic states with tunability. In this work, we investigate a unique van der Waals (vdW) material system,A2M3X4(A= K, Rb, Cs;M= Ni, Pd;X= S, Se), where transition metal kagome lattices, chalcogen honeycomb lattices and alkali metal triangular lattices coexist simultaneously. A notable feature of this material is that each Ni/Pd atom is positioned in the center of four chalcogen atoms, forming a local square-planar environment. This crystal field environment results in a low spin stateS= 0 of Ni2+/Pd2+. A systematic study of the crystal growth, crystal structure, magnetic and transport properties of two representative compounds, Rb2Ni3S4and Cs2Ni3Se4, has been carried out on powder and single crystal samples. Both compounds exhibit nonmagneticp-type semiconducting behavior, closely related to the particular chemical environment of Ni2+ions and the alkali metal intercalated vdW structure. Additionally, Cs2Ni3Se4undergoes an insulator-metal transition (IMT) in transport measurements under pressure up to 87.1 GPa without any structural phase transition, while Rb2Ni3S4shows the tendency to be metalized.
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Affiliation(s)
- Hong Du
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, People's Republic of China
| | - Yu Zheng
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, People's Republic of China
| | - Cuiying Pei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Chi-Ming Yim
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, People's Republic of China
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Yanpeng Qi
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai 201210, People's Republic of China
- Shanghai Key Laboratory of High-resolution Electron Microscopy, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Ruidan Zhong
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, People's Republic of China
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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9
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Cheng WN, Niu M, Meng Y, Han X, Qiao J, Zhang J, Zhao X. Engineering Charge Density Waves by Stackingtronics in Tantalum Disulfide. NANO LETTERS 2024; 24:6441-6449. [PMID: 38757836 DOI: 10.1021/acs.nanolett.4c01771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
In the realm of condensed matter physics and materials science, charge density waves (CDWs) have emerged as a captivating way to modulate correlated electronic phases and electron oscillations in quantum materials. However, collectively and efficiently tuning CDW order is a formidable challenge. Herein, we introduced a novel way to modulate the CDW order in 1T-TaS2 via stacking engineering. By introducing shear strain during the electrochemical exfoliation, the thermodynamically stable AA-stacked TaS2 consecutively transform into metastable ABC stacking, resulting in unique 3a × 1a CDW order. By decoupling atom coordinates, we atomically deciphered the 3D subtle structural variations in trilayer samples. As suggested by density functional theory (DFT) calculations, the origin of CDWs is presumably due to collective excitations and charge modulation. Therefore, our works shed light on a new avenue to collectively modulate the CDW order via stackingtronics and unveiled novel mechanisms for triggering CDW formation via charge modulation.
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Affiliation(s)
- Wing Ni Cheng
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Mengmeng Niu
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices & Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yuan Meng
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Xiaocang Han
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Jingsi Qiao
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices & Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jin Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
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10
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Tang J, Ding TS, Chen H, Gao A, Qian T, Huang Z, Sun Z, Han X, Strasser A, Li J, Geiwitz M, Shehabeldin M, Belosevich V, Wang Z, Wang Y, Watanabe K, Taniguchi T, Bell DC, Wang Z, Fu L, Zhang Y, Qian X, Burch KS, Shi Y, Ni N, Chang G, Xu SY, Ma Q. Dual quantum spin Hall insulator by density-tuned correlations in TaIrTe 4. Nature 2024; 628:515-521. [PMID: 38509374 DOI: 10.1038/s41586-024-07211-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
The convergence of topology and correlations represents a highly coveted realm in the pursuit of new quantum states of matter1. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order2-8, not possible in quantum Hall and Chern insulator systems. Here we report a new dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator, manifesting enhanced nonlocal transport and quantized helical edge conductance. After introducing electrons from charge neutrality, TaIrTe4 shows metallic behaviour in only a small range of charge densities but quickly goes into a new insulating state, entirely unexpected on the basis of the single-particle band structure of TaIrTe4. This insulating state could arise from a strong electronic instability near the van Hove singularities, probably leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state. The observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands through CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism2-4,9,10.
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Affiliation(s)
- Jian Tang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | | | - Hongyu Chen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anyuan Gao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Tiema Qian
- Department of Physics and Astronomy and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Zumeng Huang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Zhe Sun
- Department of Physics, Boston College, Chestnut Hill, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Xin Han
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Alex Strasser
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Jiangxu Li
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
- Min H. Kao Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - Michael Geiwitz
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | | | | | - Zihan Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yiping Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - David C Bell
- Harvard John A. Paulson School of Engineering and Applied Sciences and The Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yang Zhang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
- Min H. Kao Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, TN, USA
| | - Xiaofeng Qian
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Kenneth S Burch
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill, MA, USA.
- CIFAR Azrieli Global Scholars program, CIFAR, Toronto, Ontario, Canada.
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11
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Pham TA, Kang SH, Ozbek Y, Yoon M, Zhang P. Distance-Dependent Evolution of Electronic States in Kagome-Honeycomb Lateral Heterostructures in FeSn. ACS NANO 2024; 18:8768-8776. [PMID: 38488038 DOI: 10.1021/acsnano.3c11381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
In this work, we demonstrate the formation and electronic influence of lateral heterointerfaces in FeSn containing Kagome and honeycomb layers. Lateral heterostructures offer spatially resolved property control, enabling the integration of dissimilar materials and promoting phenomena not typically observed in vertical heterostructures. Using the molecular beam epitaxy technique, we achieve a controllable synthesis of lateral heterostructures in the Kagome metal FeSn. With scanning tunneling microscopy/spectroscopy in conjunction with first-principles calculations, we provide a comprehensive understanding of the bonding motif connecting the Fe3Sn-terminated Kagome and Sn2-terminated honeycomb surfaces. More importantly, we reveal a distance-dependent evolution of the electronic states in the vicinity of the heterointerfaces. This evolution is significantly influenced by the orbital character of the flat bands. Our findings suggest an approach to modulate the electronic properties of the Kagome lattice, which should be beneficial for the development of future quantum devices.
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Affiliation(s)
- Tuan Anh Pham
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - Seoung-Hun Kang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yasemin Ozbek
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
| | - Mina Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Pengpeng Zhang
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States
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12
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Chen H, Xing Y, Tan H, Huang L, Zheng Q, Huang Z, Han X, Hu B, Ye Y, Li Y, Xiao Y, Lei H, Qiu X, Liu E, Yang H, Wang Z, Yan B, Gao HJ. Atomically precise engineering of spin-orbit polarons in a kagome magnetic Weyl semimetal. Nat Commun 2024; 15:2301. [PMID: 38485746 PMCID: PMC10940584 DOI: 10.1038/s41467-024-46729-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
Atomically precise defect engineering is essential to manipulate the properties of emerging topological quantum materials for practical quantum applications. However, this remains challenging due to the obstacles in modifying the typically complex crystal lattice with atomic precision. Here, we report the atomically precise engineering of the vacancy-localized spin-orbit polarons in a kagome magnetic Weyl semimetal Co3Sn2S2, using scanning tunneling microscope. We achieve the step-by-step repair of the selected vacancies, leading to the formation of artificial sulfur vacancies with elaborate geometry. We find that that the bound states localized around these vacancies undergo a symmetry dependent energy shift towards Fermi level with increasing vacancy size. As the vacancy size increases, the localized magnetic moments of spin-orbit polarons become tunable and eventually become itinerantly negative due to spin-orbit coupling in the kagome flat band. These findings provide a platform for engineering atomic quantum states in topological quantum materials at the atomic scale.
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Affiliation(s)
- Hui Chen
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yuqing Xing
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Hengxin Tan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Li Huang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Qi Zheng
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Zihao Huang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xianghe Han
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Bin Hu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yuhan Ye
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yan Li
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yao Xiao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Hechang Lei
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, PR China
| | - Xianggang Qiu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Enke Liu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Haitao Yang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Ziqiang Wang
- Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Hong-Jun Gao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
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13
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Chen L, Teng X, Tan H, Winn BL, Granroth GE, Ye F, Yu DH, Mole RA, Gao B, Yan B, Yi M, Dai P. Competing itinerant and local spin interactions in kagome metal FeGe. Nat Commun 2024; 15:1918. [PMID: 38429271 PMCID: PMC10907581 DOI: 10.1038/s41467-023-44190-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 12/04/2023] [Indexed: 03/03/2024] Open
Abstract
The combination of a geometrically frustrated lattice, and similar energy scales between degrees of freedom endows two-dimensional Kagome metals with a rich array of quantum phases and renders them ideal for studying strong electron correlations and band topology. The Kagome metal, FeGe is a noted example of this, exhibiting A-type collinear antiferromagnetic (AFM) order at TN ≈ 400 K, then establishes a charge density wave (CDW) phase coupled with AFM ordered moment below TCDW ≈ 110 K, and finally forms a c-axis double cone AFM structure around TCanting ≈ 60 K. Here we use neutron scattering to demonstrate the presence of gapless incommensurate spin excitations associated with the double cone AFM structure of FeGe at temperatures well above TCanting and TCDW that merge into gapped commensurate spin waves from the A-type AFM order. Commensurate spin waves follow the Bose factor and fit the Heisenberg Hamiltonian, while the incommensurate spin excitations, emerging below TN where AFM order is commensurate, start to deviate from the Bose factor around TCDW, and peaks at TCanting. This is consistent with a critical scattering of a second order magnetic phase transition with decreasing temperature. By comparing these results with density functional theory calculations, we conclude that the incommensurate magnetic structure arises from the nested Fermi surfaces of itinerant electrons and the formation of a spin density wave order.
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Affiliation(s)
- Lebing Chen
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Xiaokun Teng
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Hengxin Tan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Barry L Winn
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Garrett E Granroth
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Feng Ye
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - D H Yu
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia
| | - R A Mole
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia
| | - Bin Gao
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ming Yi
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
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14
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Cao S, Xu C, Fukui H, Manjo T, Dong Y, Shi M, Liu Y, Cao C, Song Y. Competing charge-density wave instabilities in the kagome metal ScV 6Sn 6. Nat Commun 2023; 14:7671. [PMID: 37996409 PMCID: PMC10667248 DOI: 10.1038/s41467-023-43454-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023] Open
Abstract
Owing to its unique geometry, the kagome lattice hosts various many-body quantum states including frustrated magnetism, superconductivity, and charge-density waves (CDWs). In this work, using inelastic X-ray scattering, we discover a dynamic short-range [Formula: see text] CDW that is dominant in the kagome metal ScV6Sn6 above TCDW ≈ 91 K, competing with the [Formula: see text] CDW that orders below TCDW. The competing CDW instabilities lead to an unusual CDW formation process, with the most pronounced phonon softening and the static CDW occurring at different wavevectors. First-principles calculations indicate that the [Formula: see text] CDW is energetically favored, while a wavevector-dependent electron-phonon coupling (EPC) promotes the [Formula: see text] CDW as the ground state, and leads to enhanced electron scattering above TCDW. These findings underscore EPC-driven correlated many-body physics in ScV6Sn6 and motivate studies of emergent quantum phases in the strong EPC regime.
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Affiliation(s)
- Saizheng Cao
- Center for Correlated Matter and School of Physics, Zhejiang University, 310058, Hangzhou, China
| | - Chenchao Xu
- School of Physics, Hangzhou Normal University, 310036, Hangzhou, China
| | - Hiroshi Fukui
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan
| | - Taishun Manjo
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan
| | - Ying Dong
- Research Center for Quantum Sensing, Zhejiang Lab, 310000, Hangzhou, P. R. China
| | - Ming Shi
- Center for Correlated Matter and School of Physics, Zhejiang University, 310058, Hangzhou, China
- Photon Science Division, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - Yang Liu
- Center for Correlated Matter and School of Physics, Zhejiang University, 310058, Hangzhou, China
| | - Chao Cao
- Center for Correlated Matter and School of Physics, Zhejiang University, 310058, Hangzhou, China.
| | - Yu Song
- Center for Correlated Matter and School of Physics, Zhejiang University, 310058, Hangzhou, China.
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15
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Bravo M, McCandless GT, Baumbach RE, Wang Y, Ali MN, Chan JY. Crystal Growth and Physical Properties of Hybrid CoSn-YCo 6Ge 6 Structure Type Ln xCo 3(Ge 1-ySn y) 3 (Ln = Y, Gd). Inorg Chem 2023; 62:18049-18055. [PMID: 37870243 DOI: 10.1021/acs.inorgchem.3c02172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
There is an ongoing interest in kagome materials because they offer tunable platforms at the intersection of magnetism and electron correlation. Herein, we examine single crystals of new kagome materials, LnxCo3(Ge1-ySny)3 (Ln = Y, Gd; y = 0.11, 0.133), which were produced using the Sn flux-growth method. Unlike many of the related chemical analogues with the LnM6X6 formula (M = transition metal and X = Ge, Sn), the Y and Gd analogues crystallize in a hybrid YCo6Ge6/CoSn structure, with Sn substitution. While the Y analogue displays temperature-independent paramagnetism, magnetic measurements of the Gd analogue reveal a magnetic moment of 8.48 μB, indicating a contribution from both Gd and Co. Through anisotropic magnetic measurements, the direction of Co-magnetism can be inferred to be in plane with the kagome net, as the Co contribution is only along H//a. Crystal growth and structure determination of YxCo3(Ge,Sn)3 and GdxCo3(Ge,Sn)3, two new hybrid kagome materials of the CoSn and YCo6Ge6 structure types. Magnetic properties, heat capacity, and resistivity on single crystals are reported.
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Affiliation(s)
- Moisés Bravo
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Gregory T McCandless
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Yaojia Wang
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
- Kavli Institute of Nanoscience, Delft University of Technology, Delft 2628 CJ, The Netherlands
| | - Mazhar N Ali
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
- Kavli Institute of Nanoscience, Delft University of Technology, Delft 2628 CJ, The Netherlands
| | - Julia Y Chan
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
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16
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Wu S, Basak R, Li W, Kim JW, Ryan PJ, Lu D, Hashimoto M, Nelson C, Acevedo-Esteves R, Haley SC, Analytis JG, He Y, Frano A, Birgeneau RJ. Discovery of Charge Order in the Transition Metal Dichalcogenide Fe_{x}NbS_{2}. PHYSICAL REVIEW LETTERS 2023; 131:186701. [PMID: 37977621 DOI: 10.1103/physrevlett.131.186701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/08/2023] [Indexed: 11/19/2023]
Abstract
The Fe intercalated transition metal dichalcogenide (TMD), Fe_{1/3}NbS_{2}, exhibits remarkable resistance switching properties and highly tunable spin ordering phases due to magnetic defects. We conduct synchrotron x-ray scattering measurements on both underintercalated (x=0.32) and overintercalated (x=0.35) samples. We discover a new charge order phase in the overintercalated sample, where the excess Fe atoms lead to a zigzag antiferromagnetic order. The agreement between the charge and magnetic ordering temperatures, as well as their intensity relationship, suggests a strong magnetoelastic coupling as the mechanism for the charge ordering. Our results reveal the first example of a charge order phase among the intercalated TMD family and demonstrate the ability to stabilize charge modulation by introducing electronic correlations, where the charge order is absent in bulk 2H-NbS_{2} compared to other pristine TMDs.
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Affiliation(s)
- Shan Wu
- Department of Physics, University of California Berkeley, California 94720, USA
- Material Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Physics, Santa Clara University, Santa Clara, California 95053, USA
| | - Rourav Basak
- Department of Physics, University of California San Diego, San Diego, California 92093, USA
| | - Wenxin Li
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratories, Lemont, Illinois, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratories, Lemont, Illinois, USA
| | - Donghui Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Makoto Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Christie Nelson
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Raul Acevedo-Esteves
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Shannon C Haley
- Department of Physics, University of California Berkeley, California 94720, USA
| | - James G Analytis
- Department of Physics, University of California Berkeley, California 94720, USA
- CIFAR Quantum Materials, CIFAR, Toronto, Ontario M5G 1M1, Canada
| | - Yu He
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Alex Frano
- Department of Physics, University of California San Diego, San Diego, California 92093, USA
| | - Robert J Birgeneau
- Department of Physics, University of California Berkeley, California 94720, USA
- Material Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
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17
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Korshunov A, Hu H, Subires D, Jiang Y, Călugăru D, Feng X, Rajapitamahuni A, Yi C, Roychowdhury S, Vergniory MG, Strempfer J, Shekhar C, Vescovo E, Chernyshov D, Said AH, Bosak A, Felser C, Bernevig BA, Blanco-Canosa S. Softening of a flat phonon mode in the kagome ScV 6Sn 6. Nat Commun 2023; 14:6646. [PMID: 37863907 PMCID: PMC10589229 DOI: 10.1038/s41467-023-42186-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/29/2023] [Indexed: 10/22/2023] Open
Abstract
Geometrically frustrated kagome lattices are raising as novel platforms to engineer correlated topological electron flat bands that are prominent to electronic instabilities. Here, we demonstrate a phonon softening at the kz = π plane in ScV6Sn6. The low energy longitudinal phonon collapses at ~98 K and q = [Formula: see text] due to the electron-phonon interaction, without the emergence of long-range charge order which sets in at a different propagation vector qCDW = [Formula: see text]. Theoretical calculations corroborate the experimental finding to indicate that the leading instability is located at [Formula: see text] of a rather flat mode. We relate the phonon renormalization to the orbital-resolved susceptibility of the trigonal Sn atoms and explain the approximately flat phonon dispersion. Our data report the first example of the collapse of a kagome bosonic mode and promote the 166 compounds of kagomes as primary candidates to explore correlated flat phonon-topological flat electron physics.
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Affiliation(s)
- A Korshunov
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - H Hu
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - D Subires
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - Y Jiang
- 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
| | - D Călugăru
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - X Feng
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - A Rajapitamahuni
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - C Yi
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - S Roychowdhury
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - M G Vergniory
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - J Strempfer
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - C Shekhar
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - E Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - D Chernyshov
- Swiss-Norwegian BeamLines at European Synchrotron Radiation Facility, Grenoble, France
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - A Bosak
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - B Andrei Bernevig
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - S Blanco-Canosa
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
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18
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Zhang H, Oli BD, Zou Q, Guo X, Wang Z, Li L. Visualizing symmetry-breaking electronic orders in epitaxial Kagome magnet FeSn films. Nat Commun 2023; 14:6167. [PMID: 37794009 PMCID: PMC10550950 DOI: 10.1038/s41467-023-41831-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
Kagome lattice hosts a plethora of quantum states arising from the interplay of topology, spin-orbit coupling, and electron correlations. Here, we report symmetry-breaking electronic orders tunable by an applied magnetic field in a model Kagome magnet FeSn consisting of alternating stacks of two-dimensional Fe3Sn Kagome and Sn2 honeycomb layers. On the Fe3Sn layer terminated FeSn thin films epitaxially grown on SrTiO3(111) substrates, we observe trimerization of the Kagome lattice using scanning tunneling microscopy/spectroscopy, breaking its six-fold rotational symmetry while preserving the translational symmetry. Such a trimerized Kagome lattice shows an energy-dependent contrast reversal in dI/dV maps, which is significantly enhanced by bound states induced by Sn vacancy defects. This trimerized Kagome lattice also exhibits stripe modulations that are energy-dependent and tunable by an applied in-plane magnetic field, indicating symmetry-breaking nematicity from the entangled magnetic and charge degrees of freedom in antiferromagnet FeSn.
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Affiliation(s)
- Huimin Zhang
- Department of Physics and Astronomy, West Virginia University, Morgantown, WV, 26506, USA
- State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment, Dalian University of Technology, Dalian, 116024, China
| | - Basu Dev Oli
- Department of Physics and Astronomy, West Virginia University, Morgantown, WV, 26506, USA
| | - Qiang Zou
- Department of Physics and Astronomy, West Virginia University, Morgantown, WV, 26506, USA
| | - Xu Guo
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, Hefei National Laboratory, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Zhengfei Wang
- Hefei National Research Center for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Department of Physics, Hefei National Laboratory, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Lian Li
- Department of Physics and Astronomy, West Virginia University, Morgantown, WV, 26506, USA.
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19
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Miao H, Zhang TT, Li HX, Fabbris G, Said AH, Tartaglia R, Yilmaz T, Vescovo E, Yin JX, Murakami S, Feng XL, Jiang K, Wu XL, Wang AF, Okamoto S, Wang YL, Lee HN. Signature of spin-phonon coupling driven charge density wave in a kagome magnet. Nat Commun 2023; 14:6183. [PMID: 37793998 PMCID: PMC10550957 DOI: 10.1038/s41467-023-41957-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
The intertwining between spin, charge, and lattice degrees of freedom can give rise to unusual macroscopic quantum states, including high-temperature superconductivity and quantum anomalous Hall effects. Recently, a charge density wave (CDW) has been observed in the kagome antiferromagnet FeGe, indicative of possible intertwining physics. An outstanding question is that whether magnetic correlation is fundamental for the spontaneous spatial symmetry breaking orders. Here, utilizing elastic and high-resolution inelastic x-ray scattering, we observe a c-axis superlattice vector that coexists with the 2[Formula: see text]2[Formula: see text]1 CDW vectors in the kagome plane. Most interestingly, between the magnetic and CDW transition temperatures, the phonon dynamical structure factor shows a giant phonon-energy hardening and a substantial phonon linewidth broadening near the c-axis wavevectors, both signaling the spin-phonon coupling. By first principles and model calculations, we show that both the static spin polarization and dynamic spin excitations intertwine with the phonon to drive the spatial symmetry breaking in FeGe.
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Affiliation(s)
- H Miao
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - T T Zhang
- Department of Physics, Tokyo Institute of Technology, Okayama, Meguro-ku, Tokyo, Japan
| | - H X Li
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Advanced Materials Thrust, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China
| | - G Fabbris
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
| | - R Tartaglia
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
- "Gleb Wataghin" Institute of Physics, University of Campinas, Campinas, São Paulo, Brazil
| | - T Yilmaz
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - E Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, USA
| | - J-X Yin
- Laboratory for Quantum Emergence, Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - S Murakami
- Department of Physics, Tokyo Institute of Technology, Okayama, Meguro-ku, Tokyo, Japan
| | - X L Feng
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - K Jiang
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - X L Wu
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China
| | - A F Wang
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing, China.
| | - S Okamoto
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Y L Wang
- School of Emerging Technology, University of Science and Technology of China, Hefei, Anhui, China.
| | - H N Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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20
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Li H, Ding B, Chen J, Xi X, Zhang H, Lau YC, Wang W. Coherent magnetic and electronic structure symmetry broken in frustrated bilayer Kagome ferromagnet Fe 3Sn 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:475701. [PMID: 37557886 DOI: 10.1088/1361-648x/aceedd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 08/09/2023] [Indexed: 08/11/2023]
Abstract
In this letter, by measuring resistivity and magnetization with magnetic fieldHrotated inabplane and currentIalongcaxis, we studied the magnetic and electronic structure symmetry of frustrated topological bilayer Kagome ferromagnet Fe3Sn2. We observed that the curves of the resistivity and magnetization both showed broken two-fold symmetry from 5 K to 380 K. The further analysis indicates that there is a close causality between the spin arrangement and the electronic states in Fe3Sn2even above room temperature. These phenomena are closely related to the change in spin-orbit coupling (SOC) under the magnetic field. Our experimental results suggest that Fe3Sn2is an ideal platform to study the influence of spin arrangement on electronic state in topological materials and can also be used to design next generation magnetic devices by modulating SOC at external magnetic field.
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Affiliation(s)
- Hang Li
- School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Bei Ding
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Jie Chen
- School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xuekui Xi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Hongwei Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yong-Chang Lau
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wenhong Wang
- School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, People's Republic of China
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21
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Jiang Z, Liu Z, Ma H, Xia W, Liu Z, Liu J, Cho S, Yang Y, Ding J, Liu J, Huang Z, Qiao Y, Shen J, Jing W, Liu X, Liu J, Guo Y, Shen D. Flat bands, non-trivial band topology and rotation symmetry breaking in layered kagome-lattice RbTi 3Bi 5. Nat Commun 2023; 14:4892. [PMID: 37580381 PMCID: PMC10425367 DOI: 10.1038/s41467-023-40515-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/21/2023] [Indexed: 08/16/2023] Open
Abstract
A representative class of kagome materials, AV3Sb5 (A = K, Rb, Cs), hosts several unconventional phases such as superconductivity, [Formula: see text] non-trivial topological states, and electronic nematic states. These can often coexist with intertwined charge-density wave states. Recently, the discovery of the isostructural titanium-based single-crystals, ATi3Bi5 (A = K, Rb, Cs), which exhibit similar multiple exotic states but without the concomitant charge-density wave, has opened an opportunity to disentangle these complex states in kagome lattices. Here, we combine high-resolution angle-resolved photoemission spectroscopy and first-principles calculations to investigate the low-lying electronic structure of RbTi3Bi5. We demonstrate the coexistence of flat bands and several non-trivial states, including type-II Dirac nodal lines and [Formula: see text] non-trivial topological surface states. Our findings also provide evidence for rotational symmetry breaking in RbTi3Bi5, suggesting a directionality to the electronic structure and the possible emergence of pure electronic nematicity in this family of kagome compounds.
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Affiliation(s)
- Zhicheng Jiang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Zhengtai Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China.
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210, Shanghai, China.
| | - Haiyang Ma
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China
| | - Zhonghao Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Jishan Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210, Shanghai, China
| | - Soohyun Cho
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Yichen Yang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Jianyang Ding
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Jiayu Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Zhe Huang
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Yuxi Qiao
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Jiajia Shen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Wenchuan Jing
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Xiangqi Liu
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 230029, Hefei, China
| | - Jianpeng Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China.
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210, Shanghai, China.
| | - Dawei Shen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050, Shanghai, China.
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, 230029, Hefei, China.
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22
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Hu H, Si Q. Coupled topological flat and wide bands: Quasiparticle formation and destruction. SCIENCE ADVANCES 2023; 9:eadg0028. [PMID: 37467334 DOI: 10.1126/sciadv.adg0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 06/16/2023] [Indexed: 07/21/2023]
Abstract
Flat bands amplify correlation effects and are of extensive current interest. They provide a platform to explore both topology in correlated settings and correlation physics enriched by topology. Recent experiments in correlated kagome metals have found evidence for strange-metal behavior. A major theoretical challenge is to study the effect of local Coulomb repulsion when the band topology obstructs a real-space description. In a variant to the kagome lattice, we identify an orbital-selective Mott transition in any system of coupled topological flat and wide bands. This was made possible by the construction of exponentially localized and Kramers-doublet Wannier functions, which, in turn, leads to an effective Kondo-lattice description. Our findings show how quasiparticles are formed in such coupled topological flat-wide band systems and, equally important, how they are destroyed. Our work provides a conceptual framework for the understanding of the existing and emerging strange-metal properties in kagome metals and beyond.
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Affiliation(s)
- Haoyu Hu
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
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23
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Yang J, Yi X, Zhao Z, Xie Y, Miao T, Luo H, Chen H, Liang B, Zhu W, Ye Y, You JY, Gu B, Zhang S, Zhang F, Yang F, Wang Z, Peng Q, Mao H, Liu G, Xu Z, Chen H, Yang H, Su G, Gao H, Zhao L, Zhou XJ. Observation of flat band, Dirac nodal lines and topological surface states in Kagome superconductor CsTi 3Bi 5. Nat Commun 2023; 14:4089. [PMID: 37429852 DOI: 10.1038/s41467-023-39620-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/21/2023] [Indexed: 07/12/2023] Open
Abstract
Kagome lattices of various transition metals are versatile platforms for achieving anomalous Hall effects, unconventional charge-density wave orders and quantum spin liquid phenomena due to the strong correlations, spin-orbit coupling and/or magnetic interactions involved in such a lattice. Here, we use laser-based angle-resolved photoemission spectroscopy in combination with density functional theory calculations to investigate the electronic structure of the newly discovered kagome superconductor CsTi3Bi5, which is isostructural to the AV3Sb5 (A = K, Rb or Cs) kagome superconductor family and possesses a two-dimensional kagome network of titanium. We directly observe a striking flat band derived from the local destructive interference of Bloch wave functions within the kagome lattice. In agreement with calculations, we identify type-II and type-III Dirac nodal lines and their momentum distribution in CsTi3Bi5 from the measured electronic structures. In addition, around the Brillouin zone centre, [Formula: see text] nontrivial topological surface states are also observed due to band inversion mediated by strong spin-orbit coupling.
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Affiliation(s)
- Jiangang Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xinwei Yi
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuyang Xie
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Taimin Miao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hailan Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hao Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Liang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenpei Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuhan Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing-Yang You
- Department of Physics, Faculty of Science, National University of Singapore, Singapore, 117551, Singapore
| | - Bo Gu
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
- Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Fengfeng Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhimin Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hanqing Mao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Guodong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hui Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Haitao Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Gang Su
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
| | - Hongjun Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China.
| | - Lin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
| | - X J Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
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24
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Tan H, Yan B. Abundant Lattice Instability in Kagome Metal ScV_{6}Sn_{6}. PHYSICAL REVIEW LETTERS 2023; 130:266402. [PMID: 37450790 DOI: 10.1103/physrevlett.130.266402] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/19/2023] [Accepted: 06/13/2023] [Indexed: 07/18/2023]
Abstract
Kagome materials are emerging platforms for studying charge and spin orders. In this Letter, we have revealed a rich lattice instability in a Z_{2} kagome metal ScV_{6}Sn_{6} by first-principles calculations. Beyond verifying the sqrt[3]×sqrt[3]×3 charge density wave (CDW) order observed by the recent experiment, we further identified three more possible CDW structures, i.e., sqrt[3]×sqrt[3]×2 CDW with P6/mmm symmetry, 2×2×2 CDW with Immm symmetry, and 2×2×2 CDW with P6/mmm symmetry. The former two are more energetically favored than the sqrt[3]×sqrt[3]×3 phase, while the third one is comparable in energy. These CDW distortions involve mainly out-of-plane motions of Sc and Sn atoms, while V atoms constituting the kagome net are almost unchanged. We attribute the lattice instability to the smallness of Sc atomic radius. In contrast, such instability disappears in its sister compounds RV_{6}Sn_{6} (R is Y, or a rare-earth element), which exhibit quite similar electronic band structures to the Sc compound, because R has a larger atomic radius. Our work indicates that ScV_{6}Sn_{6} might exhibit varied CDW phases in different experimental conditions and provides insights to explore rich charge orders in kagome materials.
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Affiliation(s)
- Hengxin Tan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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25
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Hu X, Zhang RW, Ma DS, Cai Z, Geng D, Sun Z, Zhao Q, Gao J, Cheng P, Chen L, Wu K, Yao Y, Feng B. Realization of a Two-Dimensional Checkerboard Lattice in Monolayer Cu 2N. NANO LETTERS 2023. [PMID: 37321211 DOI: 10.1021/acs.nanolett.3c01111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional checkerboard lattice, the simplest line-graph lattice, has been intensively studied as a toy model, while material design and synthesis remain elusive. Here, we report theoretical prediction and experimental realization of the checkerboard lattice in monolayer Cu2N. Experimentally, monolayer Cu2N can be realized in the well-known N/Cu(100) and N/Cu(111) systems that were previously mistakenly believed to be insulators. Combined angle-resolved photoemission spectroscopy measurements, first-principles calculations, and tight-binding analysis show that both systems host checkerboard-derived hole pockets near the Fermi level. In addition, monolayer Cu2N has outstanding stability in air and organic solvents, which is crucial for further device applications.
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Affiliation(s)
- Xuegao Hu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Run-Wu Zhang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics and Beijing Key Lab of Nanophotonics Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Da-Shuai Ma
- Institute for Structure and Function & Department of Physics, Chongqing University, Chongqing 400044, China
| | - Zhihao Cai
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daiyu Geng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenyu Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiaoxiao Zhao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jisong Gao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Cheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics and Beijing Key Lab of Nanophotonics Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Baojie Feng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China
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26
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Shao S, Yin JX, Belopolski I, You JY, Hou T, Chen H, Jiang Y, Hossain MS, Yahyavi M, Hsu CH, Feng YP, Bansil A, Hasan MZ, Chang G. Intertwining of Magnetism and Charge Ordering in Kagome FeGe. ACS NANO 2023. [PMID: 37186957 DOI: 10.1021/acsnano.3c00229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Recent experiments report a charge density wave (CDW) in the antiferromagnet FeGe, but the nature of the charge ordering and the associated structural distortion remains elusive. We discuss the structural and electronic properties of FeGe. Our proposed ground state phase accurately captures atomic topographies acquired by scanning tunneling microscopy. We show that the 2 × 2 × 1 CDW likely results from the Fermi surface nesting of hexagonal-prism-shaped kagome states. FeGe is found to exhibit distortions in the positions of the Ge atoms instead of the Fe atoms in the kagome layers. Using in-depth first-principles calculations and analytical modeling, we demonstrate that this unconventional distortion is driven by the intertwining of magnetic exchange coupling and CDW interactions in this kagome material. The movement of Ge atoms from their pristine positions also enhances the magnetic moment of the Fe kagome layers. Our study indicates that magnetic kagome lattices provide a material candidate for exploring the effects of strong electronic correlations on the ground state and their implications for transport, magnetic, and optical responses in materials.
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Affiliation(s)
- Sen Shao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Jia-Xin Yin
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Ilya Belopolski
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Jing-Yang You
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551 Singapore
| | - Tao Hou
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Hongyu Chen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Yuxiao Jiang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Md Shafayat Hossain
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad Yahyavi
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Chia-Hsiu Hsu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551 Singapore
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
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27
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Duan S, You JY, Gou J, Chen J, Huang YL, Liu M, Sun S, Wang Y, Yu X, Wang L, Feng YP, Sun YY, Wee ATS, Chen W. Epitaxial Growth of Single-Layer Kagome Nanoflakes with Topological Band Inversion. ACS NANO 2022; 16:21079-21086. [PMID: 36383161 DOI: 10.1021/acsnano.2c08895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The kagome lattice has attracted intense interest with the promise of realizing topological phases built from strongly interacting electrons. However, fabricating two-dimensional (2D) kagome materials with nontrivial topology is still a key challenge. Here, we report the growth of single-layer iron germanide kagome nanoflakes by molecular beam epitaxy. Using scanning tunneling microscopy/spectroscopy, we unravel the real-space electronic localization of the kagome flat bands. First-principles calculations demonstrate the topological band inversion, suggesting the topological nature of the experimentally observed edge mode. Apart from the intrinsic topological states that potentially host chiral edge modes, the realization of kagome materials in the 2D limit also holds promise for future studies of geometric frustration.
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Affiliation(s)
- Sisheng Duan
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Jing-Yang You
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Jian Gou
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Jie Chen
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
| | - Yu Li Huang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
| | - Meizhuang Liu
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Shuo Sun
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - Yihe Wang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, 117603, Singapore
| | - Li Wang
- Institute for Advanced Study and Department of Physics, Nanchang University, Nanchang 330031, PR China
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Yi-Yang Sun
- State Key Laboratory of High-Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China
| | - Andrew T S Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
| | - Wei Chen
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
- National University of Singapore (Suzhou) Research Institute, Suzhou 215123, PR China
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28
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Abstract
A kagome lattice naturally features Dirac fermions, flat bands and van Hove singularities in its electronic structure. The Dirac fermions encode topology, flat bands favour correlated phenomena such as magnetism, and van Hove singularities can lead to instabilities towards long-range many-body orders, altogether allowing for the realization and discovery of a series of topological kagome magnets and superconductors with exotic properties. Recent progress in exploring kagome materials has revealed rich emergent phenomena resulting from the quantum interactions between geometry, topology, spin and correlation. Here we review these key developments in this field, starting from the fundamental concepts of a kagome lattice, to the realizations of Chern and Weyl topological magnetism, to various flat-band many-body correlations, and then to the puzzles of unconventional charge-density waves and superconductivity. We highlight the connection between theoretical ideas and experimental observations, and the bond between quantum interactions within kagome magnets and kagome superconductors, as well as their relation to the concepts in topological insulators, topological superconductors, Weyl semimetals and high-temperature superconductors. These developments broadly bridge topological quantum physics and correlated many-body physics in a wide range of bulk materials and substantially advance the frontier of topological quantum matter.
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29
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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. PHYSICAL REVIEW LETTERS 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] [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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30
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Control of chiral orbital currents in a colossal magnetoresistance material. Nature 2022; 611:467-472. [PMID: 36224383 DOI: 10.1038/s41586-022-05262-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/22/2022] [Indexed: 11/08/2022]
Abstract
Colossal magnetoresistance (CMR) is an extraordinary enhancement of the electrical conductivity in the presence of a magnetic field. It is conventionally associated with a field-induced spin polarization that drastically reduces spin scattering and electric resistance. Ferrimagnetic Mn3Si2Te6 is an intriguing exception to this rule: it exhibits a seven-order-of-magnitude reduction in ab plane resistivity that occurs only when a magnetic polarization is avoided1,2. Here, we report an exotic quantum state that is driven by ab plane chiral orbital currents (COC) flowing along edges of MnTe6 octahedra. The c axis orbital moments of ab plane COC couple to the ferrimagnetic Mn spins to drastically increase the ab plane conductivity (CMR) when an external magnetic field is aligned along the magnetic hard c axis. Consequently, COC-driven CMR is highly susceptible to small direct currents exceeding a critical threshold, and can induce a time-dependent, bistable switching that mimics a first-order 'melting transition' that is a hallmark of the COC state. The demonstrated current-control of COC-enabled CMR offers a new paradigm for quantum technologies.
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