1
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Beaulieu S, Dong S, Christiansson V, Werner P, Pincelli T, Ziegler JD, Taniguchi T, Watanabe K, Chernikov A, Wolf M, Rettig L, Ernstorfer R, Schüler M. Berry curvature signatures in chiroptical excitonic transitions. SCIENCE ADVANCES 2024; 10:eadk3897. [PMID: 38941460 PMCID: PMC11212730 DOI: 10.1126/sciadv.adk3897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 05/24/2024] [Indexed: 06/30/2024]
Abstract
The topology of the electronic band structure of solids can be described by its Berry curvature distribution across the Brillouin zone. We theoretically introduce and experimentally demonstrate a general methodology based on the measurement of energy- and momentum-resolved optical transition rates, allowing to reveal signatures of Berry curvature texture in reciprocal space. By performing time- and angle-resolved photoemission spectroscopy of atomically thin WSe2 using polarization-modulated excitations, we demonstrate that excitons become an asset in extracting the quantum geometrical properties of solids. We also investigate the resilience of our measurement protocol against ultrafast scattering processes following direct chiroptical transitions.
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Affiliation(s)
- Samuel Beaulieu
- Université de Bordeaux - CNRS - CEA, CELIA, UMR5107, F33405 Talence, France
| | - Shuo Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | | | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Tommaso Pincelli
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Strasse des 17 Juni 135, 10623 Berlin, Germany
| | - Jonas D. Ziegler
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Alexey Chernikov
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Martin Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Laurenz Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Ralph Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Strasse des 17 Juni 135, 10623 Berlin, Germany
| | - Michael Schüler
- Laboratory for Materials Simulations, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland
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2
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Cho W, Kang YG, Cha J, Lee DHD, Kiem DH, Oh J, Joo Y, Yer S, Kim D, Park J, Kim C, Yang Y, Kim Y, Han MJ, Yang H. Singular Hall Response from a Correlated Ferromagnetic Flat Nodal-Line Semimetal. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2402040. [PMID: 38798189 DOI: 10.1002/adma.202402040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/26/2024] [Indexed: 05/29/2024]
Abstract
Topological quantum phases are largely understood in weakly correlated systems, which have identified various quantum phenomena, such as the spin Hall effect, protected transport of helical fermions, and topological superconductivity. Robust ferromagnetic order in correlated topological materials particularly attracts attention, as it can provide a versatile platform for novel quantum devices. Here, a singular Hall response arising from a unique band structure of flat topological nodal lines in combination with electron correlation in a van der Waals ferromagnetic semimetal, Fe3GaTe2, with a high Curie temperature of Tc = 347 K is reported. High anomalous Hall conductivity violating the conventional scaling, resistivity upturn at low temperature, and a large Sommerfeld coefficient are observed in Fe3GaTe2, which implies heavy fermion features in this ferromagnetic topological material. The scanning tunneling microscopy, circular dichroism in angle-resolved photoemission spectroscopy, and theoretical calculations support the original electronic features of the material. Thus, low-dimensional Fe3GaTe2 with electronic correlation, topology, and room-temperature ferromagnetic order appears to be a promising candidate for robust quantum devices.
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Affiliation(s)
- Woohyun Cho
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Yoon-Gu Kang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Jaehun Cha
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Dong Hyun David Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Do Hoon Kiem
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Jaewhan Oh
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Yanggeun Joo
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Sangsu Yer
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Dohyun Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Jongho Park
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Yongsoo Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Graduate School of Semiconductor Technology, School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Yeongkwan Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Myung Joon Han
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Graduate School of Semiconductor Technology, School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
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3
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Brinkman SS, Tan XL, Brekke B, Mathisen AC, Finnseth Ø, Schenk RJ, Hagiwara K, Huang MJ, Buck J, Kalläne M, Hoesch M, Rossnagel K, Ou Yang KH, Lin MT, Shu GJ, Chen YJ, Tusche C, Bentmann H. Chirality-Driven Orbital Angular Momentum and Circular Dichroism in CoSi. PHYSICAL REVIEW LETTERS 2024; 132:196402. [PMID: 38804933 DOI: 10.1103/physrevlett.132.196402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 03/20/2024] [Indexed: 05/29/2024]
Abstract
Chiral crystals and molecules were recently predicted to form an intriguing platform for unconventional orbital physics. Here, we report the observation of chirality-driven orbital textures in the bulk electronic structure of CoSi, a prototype member of the cubic B20 family of chiral crystals. Using circular dichroism in soft x-ray angle-resolved photoemission, we demonstrate the formation of a bulk orbital-angular-momentum texture and monopolelike orbital-momentum locking that depends on crystal handedness. We introduce the intrinsic chiral circular dichroism, icCD, as a differential photoemission observable and a natural probe of chiral electron states. Our findings render chiral crystals promising for spin-orbitronics applications.
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Affiliation(s)
- Stefanie Suzanne Brinkman
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Xin Liang Tan
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich, Jülich 52425, Germany
- Faculty of Physics, University of Duisburg-Essen, Duisburg 47057, Germany
| | - Bjørnulf Brekke
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Anders Christian Mathisen
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Øyvind Finnseth
- Department of Materials Science and Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Richard Justin Schenk
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Kenta Hagiwara
- Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich, Jülich 52425, Germany
- Faculty of Physics, University of Duisburg-Essen, Duisburg 47057, Germany
| | - Meng-Jie Huang
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, DESY, 22607 Hamburg, Germany
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Jens Buck
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, DESY, 22607 Hamburg, Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Matthias Kalläne
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, DESY, 22607 Hamburg, Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Moritz Hoesch
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Kai Rossnagel
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, DESY, 22607 Hamburg, Germany
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Kui-Hon Ou Yang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Minn-Tsong Lin
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Guo-Jiun Shu
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
| | - Ying-Jiun Chen
- Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich, Jülich 52425, Germany
- Faculty of Physics, University of Duisburg-Essen, Duisburg 47057, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Christian Tusche
- Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich, Jülich 52425, Germany
- Faculty of Physics, University of Duisburg-Essen, Duisburg 47057, Germany
| | - Hendrik Bentmann
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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4
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Rong R, Liu Y, Nie X, Zhang W, Zhang Z, Liu Y, Guo W. The Interaction of 2D Materials With Circularly Polarized Light. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206191. [PMID: 36698292 PMCID: PMC10074140 DOI: 10.1002/advs.202206191] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/16/2022] [Indexed: 06/17/2023]
Abstract
2D materials (2DMs), due to spin-valley locking degree of freedom, exhibit strongly bound exciton and chiral optical selection rules and become promising material candidates for optoelectronic and spin/valleytronic devices. Over the last decade, the manifesting of 2D materials by circularly polarized lights expedites tremendous fascinating phenomena, such as valley/exciton Hall effect, Moiré exciton, optical Stark effect, circular dichroism, circularly polarized photoluminescence, and spintronic property. In this review, recent advance in the interaction of circularly polarized light with 2D materials covering from graphene, black phosphorous, transition metal dichalcogenides, van der Waals heterostructures as well as small proportion of quasi-2D perovskites and topological materials, is overviewed. The confronted challenges and theoretical and experimental opportunities are also discussed, attempting to accelerate the prosperity of chiral light-2DMs interactions.
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Affiliation(s)
- Rong Rong
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Ying Liu
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Xuchen Nie
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Wei Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Zhuhua Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Yanpeng Liu
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
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5
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Spin-polarized spatially indirect excitons in a topological insulator. Nature 2023; 614:249-255. [PMID: 36755173 DOI: 10.1038/s41586-022-05567-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 11/16/2022] [Indexed: 02/10/2023]
Abstract
The exciton, a bound state of an electron and a hole, is a fundamental quasiparticle induced by coherent light-matter interactions in semiconductors. When the electrons and holes are in distinct spatial locations, spatially indirect excitons are formed with a much longer lifetime and a higher condensation temperature. One of the ultimate frontiers in this field is to create long-lived excitonic topological quasiparticles by driving exciton states with topological properties, to simultaneously leverage both topological effects and correlation1,2. Here we reveal the existence of a transient excitonic topological surface state (TSS) in a topological insulator, Bi2Te3. By using time-, spin- and angle-resolved photoemission spectroscopy, we directly follow the formation of a long-lived exciton state as revealed by an intensity buildup below the bulk-TSS mixing point and an anomalous band renormalization of the continuously connected TSS in the momentum space. Such a state inherits the spin-polarization of the TSS and is spatially indirect along the z axis, as it couples photoinduced surface electrons and bulk holes in the same momentum range, which ultimately leads to an excitonic state of the TSS. These results establish Bi2Te3 as a possible candidate for the excitonic condensation of TSSs3 and, in general, opens up a new paradigm for exploring the momentum space emergence of other spatially indirect excitons, such as moiré and quantum well excitons4-6, and for the study of non-equilibrium many-body topological physics.
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6
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Schüler M, Schmitt T, Werner P. Probing magnetic orbitals and Berry curvature with circular dichroism in resonant inelastic X-ray scattering. NPJ QUANTUM MATERIALS 2023; 8:6. [PMID: 38666242 PMCID: PMC11041711 DOI: 10.1038/s41535-023-00538-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/04/2023] [Indexed: 04/28/2024]
Abstract
Resonant inelastic X-ray scattering (RIXS) can probe localized excitations at selected atoms in materials, including particle-hole transitions between the valence and conduction bands. These transitions are governed by fundamental properties of the corresponding Bloch wave functions, including orbital and magnetic degrees of freedom, and quantum geometric properties such as the Berry curvature. In particular, orbital angular momentum (OAM), which is closely linked to the Berry curvature, can exhibit a nontrivial momentum dependence. We demonstrate how information on such OAM textures can be extracted from the circular dichroism in RIXS. Based on accurate modeling with a first-principles treatment of the key ingredient-the light-matter interaction-we simulate dichroic RIXS spectra for the prototypical transition-metal dichalcogenide MoSe2 and the two-dimensional topological insulator 1T'-MoS2. Guided by an intuitive picture of the optical selection rules, we discuss how the momentum-dependent OAM manifests itself in the dichroic RIXS signal if one controls the momentum transfer. Our calculations are performed for typical experimental geometries and parameter regimes, and demonstrate the possibility of observing the predicted circular dichroism in forthcoming experiments. Thus, our work establishes a new avenue for observing Berry curvature and topological states in quantum materials.
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Affiliation(s)
- Michael Schüler
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratory for Materials Simulations, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Thorsten Schmitt
- Photon Science Division, Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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7
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Zhang Y, Kalappattil V, Liu C, Mehraeen M, Zhang SSL, Ding J, Erugu U, Chen Z, Tian J, Liu K, Tang J, Wu M. Large magnetoelectric resistance in the topological Dirac semimetal α-Sn. SCIENCE ADVANCES 2022; 8:eabo0052. [PMID: 35905193 PMCID: PMC9337753 DOI: 10.1126/sciadv.abo0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The spin-momentum locking of surface states in topological materials can produce a resistance that scales linearly with magnetic and electric fields. Such a bilinear magnetoelectric resistance (BMER) effect offers a new approach for information reading and field sensing applications, but the effects demonstrated so far are too weak or for low temperatures. This article reports the first observation of BMER effects in topological Dirac semimetals; the BMER responses were measured at room temperature and were substantially stronger than those reported previously. The experiments used topological Dirac semimetal α-Sn thin films grown on silicon substrates. The films showed BMER responses that are 106 times larger than previously measured at room temperature and are also larger than those previously obtained at low temperatures. These results represent a major advance toward realistic BMER applications. Significantly, the data also yield the first characterization of three-dimensional Fermi-level spin texture of topological surface states in α-Sn.
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Affiliation(s)
- Yuejie Zhang
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | | | - Chuanpu Liu
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
| | - M. Mehraeen
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Steven S.-L. Zhang
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jinjun Ding
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
| | - Uppalaiah Erugu
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Zhijie Chen
- Physics Department, Georgetown University, Washington, DC 20057, USA
| | - Jifa Tian
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC 20057, USA
| | - Jinke Tang
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Mingzhong Wu
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
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8
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Schrunk B, Kushnirenko Y, Kuthanazhi B, Ahn J, Wang LL, O'Leary E, Lee K, Eaton A, Fedorov A, Lou R, Voroshnin V, Clark OJ, Sánchez-Barriga J, Bud'ko SL, Slager RJ, Canfield PC, Kaminski A. Emergence of Fermi arcs due to magnetic splitting in an antiferromagnet. Nature 2022; 603:610-615. [PMID: 35322253 DOI: 10.1038/s41586-022-04412-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/08/2022] [Indexed: 11/09/2022]
Abstract
The Fermi surface plays an important role in controlling the electronic, transport and thermodynamic properties of materials. As the Fermi surface consists of closed contours in the momentum space for well-defined energy bands, disconnected sections known as Fermi arcs can be signatures of unusual electronic states, such as a pseudogap1. Another way to obtain Fermi arcs is to break either the time-reversal symmetry2 or the inversion symmetry3 of a three-dimensional Dirac semimetal, which results in formation of pairs of Weyl nodes that have opposite chirality4, and their projections are connected by Fermi arcs at the bulk boundary3,5-12. Here, we present experimental evidence that pairs of hole- and electron-like Fermi arcs emerge below the Neel temperature (TN) in the antiferromagnetic state of cubic NdBi due to a new magnetic splitting effect. The observed magnetic splitting is unusual, as it creates bands of opposing curvature, which change with temperature and follow the antiferromagnetic order parameter. This is different from previous theoretically considered13,14 and experimentally reported cases15,16 of magnetic splitting, such as traditional Zeeman and Rashba, in which the curvature of the bands is preserved. Therefore, our findings demonstrate a type of magnetic band splitting in the presence of a long-range antiferromagnetic order that is not readily explained by existing theoretical ideas.
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Affiliation(s)
| | - Yevhen Kushnirenko
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - Brinda Kuthanazhi
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - Junyeong Ahn
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Evan O'Leary
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - Kyungchan Lee
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.,Physikalisches Institut, Universität Würzburg, Würzburg, Germany.,Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany
| | - Andrew Eaton
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - Alexander Fedorov
- Leibniz Institute for Solid State and Materials Research, Dresden, Germany.,Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Rui Lou
- Leibniz Institute for Solid State and Materials Research, Dresden, Germany.,School of Physical Science and Technology, Lanzhou University, Lanzhou, China
| | | | - Oliver J Clark
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | | | - Sergey L Bud'ko
- Ames Laboratory, Ames, Iowa, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - Robert-Jan Slager
- Department of Physics, Harvard University, Cambridge, MA, USA. .,TCM Group, Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Paul C Canfield
- Ames Laboratory, Ames, Iowa, USA. .,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.
| | - Adam Kaminski
- Ames Laboratory, Ames, Iowa, USA. .,Department of Physics and Astronomy, Iowa State University, Ames, IA, USA.
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9
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Flavell W. Spiers Memorial Lecture: Prospects for photoelectron spectroscopy. Faraday Discuss 2022; 236:9-57. [DOI: 10.1039/d2fd00071g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An overview is presented of recent advances in photoelectron spectroscopy, focussing on advances in in situ and time-resolved measurements, and in extending the sampling depth of the technique. The future...
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10
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Vidal RC, Bentmann H, Facio JI, Heider T, Kagerer P, Fornari CI, Peixoto TRF, Figgemeier T, Jung S, Cacho C, Büchner B, van den Brink J, Schneider CM, Plucinski L, Schwier EF, Shimada K, Richter M, Isaeva A, Reinert F. Orbital Complexity in Intrinsic Magnetic Topological Insulators MnBi_{4}Te_{7} and MnBi_{6}Te_{10}. PHYSICAL REVIEW LETTERS 2021; 126:176403. [PMID: 33988442 DOI: 10.1103/physrevlett.126.176403] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 01/09/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of the magnetic van der Waals compounds MnBi_{4}Te_{7} and MnBi_{6}Te_{10}, the n=1 and 2 members of a modular (Bi_{2}Te_{3})_{n}(MnBi_{2}Te_{4}) series, which have attracted recent interest as intrinsic magnetic topological insulators. Combining circular dichroic, spin-resolved and photon-energy-dependent ARPES measurements with calculations based on density functional theory, we unveil complex momentum-dependent orbital and spin textures in the surface electronic structure and disentangle topological from trivial surface bands. We find that the Dirac-cone dispersion of the topologial surface state is strongly perturbed by hybridization with valence-band states for Bi_{2}Te_{3}-terminated surfaces but remains preserved for MnBi_{2}Te_{4}-terminated surfaces. Our results firmly establish the topologically nontrivial nature of these magnetic van der Waals materials and indicate that the possibility of realizing a quantized anomalous Hall conductivity depends on surface termination.
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Affiliation(s)
- R C Vidal
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - H Bentmann
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - J I Facio
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
| | - T Heider
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - P Kagerer
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - C I Fornari
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - T R F Peixoto
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - T Figgemeier
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - S Jung
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
- Department of Physics, Gyeongsang National University, Jinju 52828, Korea
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - B Büchner
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - J van den Brink
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - C M Schneider
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - L Plucinski
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - E F Schwier
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan
| | - K Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan
| | - M Richter
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Dresden Center for Computational Materials Science (DCMS), Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - A Isaeva
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Department of Physics, Gyeongsang National University, Jinju 52828, Korea
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, The Netherlands, EU
| | - F Reinert
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
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11
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Stolyarov VS, Sheina VA, Khokhlov DA, Vlaic S, Pons S, Aubin H, Akzyanov RS, Vasenko AS, Menshchikova TV, Chulkov EV, Golubov AA, Cren T, Roditchev D. Disorder-Promoted Splitting in Quasiparticle Interference at Nesting Vectors. J Phys Chem Lett 2021; 12:3127-3134. [PMID: 33755482 DOI: 10.1021/acs.jpclett.1c00462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Inelastic interactions of quantum systems with the environment usually wash coherent effects out. In the case of Friedel oscillations, the presence of disorder leads to a fast decay of the oscillation amplitude. Here we show both experimentally and theoretically that in three-dimensional topological insulator Bi2Te3 there is a nesting-induced splitting of coherent scattering vectors which follows a peculiar evolution in energy. The effect becomes experimentally observable when the lifetime of quasiparticles shortens due to disorder. The amplitude of the splitting allows an evaluation of the lifetime of the electrons. A similar phenomenon should be observed in any system with a well-defined scattering vector regardless of its topological properties.
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Affiliation(s)
- V S Stolyarov
- Laboratoire de Physique et d'Étude des Matériaux (LPEM), UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne Université, 75005 Paris, France
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- Dukhov Research Institute of Automatics (VNIIA), 127055 Moscow, Russia
| | - V A Sheina
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- C2N, UMR-9001, CNRS, Paris-Saclay Université, 91120 Palaiseau, France
| | - D A Khokhlov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- Dukhov Research Institute of Automatics (VNIIA), 127055 Moscow, Russia
- Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow, Russia
| | - S Vlaic
- Laboratoire de Physique et d'Étude des Matériaux (LPEM), UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne Université, 75005 Paris, France
| | - S Pons
- Laboratoire de Physique et d'Étude des Matériaux (LPEM), UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne Université, 75005 Paris, France
| | - H Aubin
- Laboratoire de Physique et d'Étude des Matériaux (LPEM), UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne Université, 75005 Paris, France
- C2N, UMR-9001, CNRS, Paris-Saclay Université, 91120 Palaiseau, France
| | - R S Akzyanov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- Dukhov Research Institute of Automatics (VNIIA), 127055 Moscow, Russia
- Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow, Russia
| | - A S Vasenko
- HSE University, 101000 Moscow, Russia
- I. E. Tamm Department of Theoretical Physics, P. N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - E V Chulkov
- HSE University, 101000 Moscow, Russia
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, San Sebastián/Donostia, 20018 Basque Country, Spain
| | - A A Golubov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - T Cren
- INSP, UMR-7588, Sorbonne Université, CNRS, 75005 Paris, France
| | - D Roditchev
- Laboratoire de Physique et d'Étude des Matériaux (LPEM), UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne Université, 75005 Paris, France
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- INSP, UMR-7588, Sorbonne Université, CNRS, 75005 Paris, France
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12
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King PDC, Picozzi S, Egdell RG, Panaccione G. Angle, Spin, and Depth Resolved Photoelectron Spectroscopy on Quantum Materials. Chem Rev 2021; 121:2816-2856. [PMID: 33346644 DOI: 10.1021/acs.chemrev.0c00616] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of X-ray based electron spectroscopies in determining chemical, electronic, and magnetic properties of solids has been well-known for several decades. A powerful approach is angle-resolved photoelectron spectroscopy, whereby the kinetic energy and angle of photoelectrons emitted from a sample surface are measured. This provides a direct measurement of the electronic band structure of crystalline solids. Moreover, it yields powerful insights into the electronic interactions at play within a material and into the control of spin, charge, and orbital degrees of freedom, central pillars of future solid state science. With strong recent focus on research of lower-dimensional materials and modified electronic behavior at surfaces and interfaces, angle-resolved photoelectron spectroscopy has become a core technique in the study of quantum materials. In this review, we provide an introduction to the technique. Through examples from several topical materials systems, including topological insulators, transition metal dichalcogenides, and transition metal oxides, we highlight the types of information which can be obtained. We show how the combination of angle, spin, time, and depth-resolved experiments are able to reveal "hidden" spectral features, connected to semiconducting, metallic and magnetic properties of solids, as well as underlining the importance of dimensional effects in quantum materials.
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Affiliation(s)
- Phil D C King
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche, CNR-SPIN, Via dei Vestini 31, Chieti 66100, Italy
| | - Russell G Egdell
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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13
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Hedayat H, Bugini D, Yi H, Chen C, Zhou X, Cerullo G, Dallera C, Carpene E. Ultrafast evolution of bulk, surface and surface resonance states in photoexcited [Formula: see text]. Sci Rep 2021; 11:4924. [PMID: 33649414 PMCID: PMC7921141 DOI: 10.1038/s41598-021-83848-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/05/2021] [Indexed: 11/09/2022] Open
Abstract
We use circular dichroism (CD) in time- and angle-resolved photoemission spectroscopy (trARPES) to measure the femtosecond charge dynamics in the topological insulator (TI) [Formula: see text]. We detect clear CD signatures from topological surface states (TSS) and surface resonance (SR) states. In time-resolved measurements, independently from the pump polarization or intensity, the CD shows a dynamics which provides access to the unexplored electronic evolution in unoccupied states of [Formula: see text]. In particular, we are able to disentangle the unpolarized electron dynamics in the bulk states from the spin-textured TSS and SR states on the femtosecond timescale. Our study demonstrates that photoexcitation mainly involves the bulk states and is followed by sub-picosecond transport to the surface. This provides essential details on intra- and interband scattering in the relaxation process of TSS and SR states. Our results reveal the significant role of SRs in the subtle ultrafast interaction between bulk and surface states of TIs.
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Affiliation(s)
- Hamoon Hedayat
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
| | - Davide Bugini
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
| | - Hemian Yi
- National Lab for Superconductivity, Institute of Physics, Chinese Academy of Science, Beijing, 100190 China
| | - Chaoyu Chen
- National Lab for Superconductivity, Institute of Physics, Chinese Academy of Science, Beijing, 100190 China
| | - Xingjiang Zhou
- National Lab for Superconductivity, Institute of Physics, Chinese Academy of Science, Beijing, 100190 China
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
| | - Claudia Dallera
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
| | - Ettore Carpene
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
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14
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He P, Isobe H, Zhu D, Hsu CH, Fu L, Yang H. Quantum frequency doubling in the topological insulator Bi 2Se 3. Nat Commun 2021; 12:698. [PMID: 33514744 PMCID: PMC7846578 DOI: 10.1038/s41467-021-20983-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/06/2021] [Indexed: 11/09/2022] Open
Abstract
The nonlinear Hall effect due to Berry curvature dipole (BCD) induces frequency doubling, which was recently observed in time-reversal-invariant materials. Here we report novel electric frequency doubling in the absence of BCD on a surface of the topological insulator Bi2Se3 under zero magnetic field. We observe that the frequency-doubling voltage transverse to the applied ac current shows a threefold rotational symmetry, whereas it forbids BCD. One of the mechanisms compatible with the symmetry is skew scattering, arising from the inherent chirality of the topological surface state. We introduce the Berry curvature triple, a high-order moment of the Berry curvature, to explain skew scattering under the threefold rotational symmetry. Our work paves the way to obtain a giant second-order nonlinear electric effect in high mobility quantum materials, as the skew scattering surpasses other mechanisms in the clean limit. Berry curvature dipole (BCD) leads to the nonlinear Hall effect manifested as a frequency doubling in topological materials. Here, the authors report electric frequency doubling in the absence of BCD and magnetic field on a surface of Bi2Se3 due to skew scattering arising from inherent chirality of the topological surface states.
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Affiliation(s)
- Pan He
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.,Institute for Nanoelectronic devices and Quantum computing, Fudan University, Shanghai, 200433, China
| | - Hiroki Isobe
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Dapeng Zhu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Chuang-Han Hsu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.
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15
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Beaulieu S, Schusser J, Dong S, Schüler M, Pincelli T, Dendzik M, Maklar J, Neef A, Ebert H, Hricovini K, Wolf M, Braun J, Rettig L, Minár J, Ernstorfer R. Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions. PHYSICAL REVIEW LETTERS 2020; 125:216404. [PMID: 33274965 DOI: 10.1103/physrevlett.125.216404] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/13/2020] [Indexed: 06/12/2023]
Abstract
We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe_{2} for different crystal orientations linked to each other by time-reversal symmetry. We introduce a new observable called time-reversal dichroism in photoelectron angular distributions (TRDAD), which quantifies the modulation of the photoemission intensity upon effective time-reversal operation. We demonstrate that the hidden orbital pseudospin texture leaves its imprint on TRDAD, due to multiple orbital interference effects in photoemission. Our experimental results are in quantitative agreement with both the tight-binding model and state-of-the-art fully relativistic calculations performed using the one-step model of photoemission. While spin-resolved ARPES probes the spin component of entangled spin-orbital texture in multiorbital systems, we unambiguously demonstrate that TRDAD reveals its orbital pseudospin texture counterpart.
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Affiliation(s)
- S Beaulieu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - J Schusser
- Laboratoire de Physique des Matériaux et Surfaces, CY Cergy Paris Université, 95031 Cergy-Pontoise, France
- New Technologies-Research Center, University of West Bohemia, 30614 Pilsen, Czech Republic
| | - S Dong
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - M Schüler
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T Pincelli
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - M Dendzik
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden
| | - J Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - A Neef
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - H Ebert
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 11, 81377 München, Germany
| | - K Hricovini
- Laboratoire de Physique des Matériaux et Surfaces, CY Cergy Paris Université, 95031 Cergy-Pontoise, France
- LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F-91191 Gif-sur-Yvette Cedex, France
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - J Braun
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 11, 81377 München, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - J Minár
- New Technologies-Research Center, University of West Bohemia, 30614 Pilsen, Czech Republic
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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16
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Vasilyev D, Medjanik K, Babenkov S, Ellguth M, Schönhense G, Elmers HJ. Relation between spin-orbit induced spin polarization, Fano-effect and circular dichroism in soft x-ray photoemission. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:135501. [PMID: 31796649 DOI: 10.1088/1361-648x/ab5e70] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A Feynman diagram analysis of photoemission probabilities suggests a relation between two final-state spin polarization effects, the optical spin-orientation originating from the interaction with circularly polarized light ([Formula: see text], Fano effect) and the spin polarization induced by the spin-orbit scattering ([Formula: see text], Mott effect). The analysis predicts that [Formula: see text] is proportional to the product of [Formula: see text] and the circular dichroism in the angular distribution (CDAD) of photoelectrons. To confirm this prediction, the spin polarization of photoelectrons excited by soft x-ray radiation from initial spin-degenerate bulk states of tungsten using time-of-flight momentum microscopy with parallel spin detection has been measured. By measurement of four independent photoemission intensities for two opposite spin directions and opposite photon helicity, CDAD, Fano, and Mott effect are distinguished. The results confirm the prediction from the Feynman diagram analysis.
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Affiliation(s)
- Dmitry Vasilyev
- Institut für Physik, Johannes-Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
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17
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Kang M, Ye L, Fang S, You JS, Levitan A, Han M, Facio JI, Jozwiak C, Bostwick A, Rotenberg E, Chan MK, McDonald RD, Graf D, Kaznatcheev K, Vescovo E, Bell DC, Kaxiras E, van den Brink J, Richter M, Prasad Ghimire M, Checkelsky JG, Comin R. Dirac fermions and flat bands in the ideal kagome metal FeSn. NATURE MATERIALS 2020; 19:163-169. [PMID: 31819211 DOI: 10.1038/s41563-019-0531-0] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
A kagome lattice of 3d transition metal ions is a versatile platform for correlated topological phases hosting symmetry-protected electronic excitations and magnetic ground states. However, the paradigmatic states of the idealized two-dimensional kagome lattice-Dirac fermions and flat bands-have not been simultaneously observed. Here, we use angle-resolved photoemission spectroscopy and de Haas-van Alphen quantum oscillations to reveal coexisting surface and bulk Dirac fermions as well as flat bands in the antiferromagnetic kagome metal FeSn, which has spatially decoupled kagome planes. Our band structure calculations and matrix element simulations demonstrate that the bulk Dirac bands arise from in-plane localized Fe-3d orbitals, and evidence that the coexisting Dirac surface state realizes a rare example of fully spin-polarized two-dimensional Dirac fermions due to spin-layer locking in FeSn. The prospect to harness these prototypical excitations in a kagome lattice is a frontier of great promise at the confluence of topology, magnetism and strongly correlated physics.
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Affiliation(s)
- Mingu Kang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Linda Ye
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shiang Fang
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Jhih-Shih You
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Abe Levitan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Minyong Han
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jorge I Facio
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mun K Chan
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Ross D McDonald
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - David Graf
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | | | - Elio Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA
| | - David C Bell
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Nanoscale systems, Harvard University, Cambridge, MA, USA
| | - Efthimios Kaxiras
- Department of Physics, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Jeroen van den Brink
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Manuel Richter
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Dresden Center for Computational Materials Science (DCMS), TU Dresden, Dresden, Germany
| | - Madhav Prasad Ghimire
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Joseph G Checkelsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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18
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Pozo O, Repellin C, Grushin AG. Quantization in Chiral Higher Order Topological Insulators: Circular Dichroism and Local Chern Marker. PHYSICAL REVIEW LETTERS 2019; 123:247401. [PMID: 31922878 DOI: 10.1103/physrevlett.123.247401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Indexed: 06/10/2023]
Abstract
The robust quantization of observables in units of universal constants is a hallmark of topological phases. We show that chiral higher order topological insulators (HOTIs), bulk insulators with chiral hinge states, present two unusual features related to quantization. First, we show that circular dichroism is quantized to an integer or zero depending on the orientation of the sample. This probe locates the hinge states, and can be used to distinguish different types of chiral HOTIs. Second, we find that the average of the local Chern marker over a single surface, an observable related to the surface Hall conductivity known to be quantized in the infinite slab geometry, is nonuniversal for a finite surface. This is due to a nonuniversal contribution of the hinge states, previously unaccounted for, that distinguishes surfaces of chiral HOTIs from Chern insulators. Our findings are relevant to establish higher order topology in systems such as the axion insulator candidate EuIn_{2}As_{2}, and cold atomic realizations.
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Affiliation(s)
- Oscar Pozo
- Instituto de Ciencia de Materiales de Madrid, and CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Cécile Repellin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Adolfo G Grushin
- University Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
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19
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Sie EJ, Rohwer T, Lee C, Gedik N. Time-resolved XUV ARPES with tunable 24-33 eV laser pulses at 30 meV resolution. Nat Commun 2019; 10:3535. [PMID: 31388015 PMCID: PMC6684652 DOI: 10.1038/s41467-019-11492-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 07/15/2019] [Indexed: 11/09/2022] Open
Abstract
High harmonic generation of ultrafast laser pulses can be used to perform angle-resolved photoemission spectroscopy (ARPES) to map the electronic band structure of materials with femtosecond time resolution. However, currently it is difficult to reach high momenta with narrow energy resolution. Here, we combine a gas phase extreme ultraviolet (XUV) femtosecond light source, an XUV monochromator, and a time-of-flight electron analyzer to develop XUV-based time-resolved ARPES. Our technique can produce tunable photon energy between 24-33 eV with an unprecedented energy resolution of 30 meV and time resolution of 200 fs. This technique enables time-, energy- and momentum-resolved investigation of the nonequilibrium dynamics of electrons in materials with a full access to their first Brillouin zone. We evaluate the performance of this setup through exemplary measurements on various quantum materials, including WTe2, WSe2, TiSe2, and Bi2Sr2CaCu2O8+δ.
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Affiliation(s)
- Edbert J Sie
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Timm Rohwer
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Changmin Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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20
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Hricovini K, Richter MC, Heckmann O, Nicolaï L, Mariot JM, Minár J. Topological electronic structure and Rashba effect in Bi thin layers: theoretical predictions and experiments. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:283001. [PMID: 30933942 DOI: 10.1088/1361-648x/ab1529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The goal of the present review is to cross-compare theoretical predictions with selected experimental results on bismuth thin films exhibiting topological properties and a strong Rashba effect. The theoretical prediction that a single free-standing Bi(1 1 1) bilayer is a topological insulator has triggered a large series of studies of ultrathin Bi(1 1 1) films grown on various substrates. Using selected examples we review theoretical predictions of atomic and electronic structure of Bi thin films exhibiting topological properties due to interaction with a substrate. We also survey experimental signatures of topological surface states and Rashba effect, as obtained mostly by angle- and spin-resolved photoelectron spectroscopy.
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Affiliation(s)
- K Hricovini
- Laboratoire de Physique des Matériaux et des Surfaces, Université de Cergy-Pontoise, 5 mail Gay-Lussac, 95031 Cergy-Pontoise, France. DRF, IRAMIS, SPEC-CNRS/UMR 3680, Bât. 772, L'Orme des Merisiers, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
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21
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He P, Zhang SSL, Zhu D, Shi S, Heinonen OG, Vignale G, Yang H. Nonlinear Planar Hall Effect. PHYSICAL REVIEW LETTERS 2019; 123:016801. [PMID: 31386424 DOI: 10.1103/physrevlett.123.016801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 05/07/2019] [Indexed: 06/10/2023]
Abstract
An intriguing property of a three-dimensional (3D) topological insulator (TI) is the existence of surface states with spin-momentum locking, which offers a new frontier of exploration in spintronics. Here, we report the observation of a new type of Hall effect in a 3D TI Bi_{2}Se_{3} film. The Hall resistance scales linearly with both the applied electric and magnetic fields and exhibits a π/2 angle offset with respect to its longitudinal counterpart, in contrast to the usual angle offset of π/4 between the linear planar Hall effect and the anisotropic magnetoresistance. This novel nonlinear planar Hall effect originates from the conversion of a nonlinear transverse spin current to a charge current due to the concerted actions of spin-momentum locking and time-reversal symmetry breaking, which also exists in a wide class of noncentrosymmetric materials with a large span of magnitude. It provides a new way to characterize and utilize the nonlinear spin-to-charge conversion in a variety of topological quantum materials.
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Affiliation(s)
- Pan He
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, 117576 Singapore
| | - Steven S-L Zhang
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA
| | - Dapeng Zhu
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, 117576 Singapore
| | - Shuyuan Shi
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, 117576 Singapore
| | - Olle G Heinonen
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Giovanni Vignale
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, 117576 Singapore
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22
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Yang M, Wang J, Zhao Y, He L, Ji C, Liu X, Zhou H, Wu Z, Wang X, Jiang Y. Three-Dimensional Topological Insulator Bi 2Te 3/Organic Thin Film Heterojunction Photodetector with Fast and Wideband Response from 450 to 3500 Nanometers. ACS NANO 2019; 13:755-763. [PMID: 30566317 DOI: 10.1021/acsnano.8b08056] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the pursuit of broadband photodetection materials from visible to mid-IR region, the fresh three-dimensional topological insulators (3D TIs) are theoretically predicted to be a promising candidate due to its Dirac-like stable surface state and high absorption rate. In this work, a self-powered inorganic/organic heterojunction photodetector based on n-type 3D TIs Bi2Te3 combined with p-type pentacene thin film was designed and fabricated. Surprisingly, it was found that the Bi2Te3/pentacene heterojunction photodetector exhibited a fast and wideband response from 450 to 3500 nm. The optimized responsivity of photodetector reached 14.89 A/W, along with the fast response time of 1.89 ms and the ultrahigh external quantum efficiency of 2840%. Moreover, at the mid-IR 3500 nm, our devices demonstrated a responsivity of 1.55 AW-1, which was several orders of magnitude higher than that of previous 3D TIs photodetector. These excellent properties indicate that the inorganic/organic heterojunction, that is, the combination of 3D TIs with organic materials, is an exciting structure for high performance photodetectors in the wideband detection region. On account of the fact that the device is constructed on mica substrate, this work also represents a potential scenario for flexible optoelectronic devices.
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Affiliation(s)
- Ming Yang
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Jun Wang
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Yafei Zhao
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , P.R. China
| | - Liang He
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , P.R. China
| | - Chunhui Ji
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Xianchao Liu
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Hongxi Zhou
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Zhiming Wu
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Xinran Wang
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , P.R. China
| | - Yadong Jiang
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
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23
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Peng YF, Dai CM, Shen HZ, Yi XX. Optically tunable spin texture of the surface state for Bi 2Se 3 and SmB 6 topological insulators. OPTICS EXPRESS 2018; 26:18906-18919. [PMID: 30114150 DOI: 10.1364/oe.26.018906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
The spin texture of the surface state for topological insulators can be manipulated by the polarization of light, which might play a potential role in the applications in spintronics. However, the study so far in this direction mainly focuses on the classical light-topological-insulators interactions; TIs coupled to quantized light remains barely explored. In this paper, we develop a formalism to deal with this issue of spin texture of the surface state for topological insulators (for example Bi2Se3 and SmB6) irradiated by a quantum field, and we find that the coupling between an electron and a single-mode quantum field modulates only the arrow length that represents the spin polarization of a topological surface state. Specifically, when the photon number of a single-mode quantum field is fixed, the azimuth angle between the quantum light and the material surface manipulates the spin textures along the constant energy contour rotating (clockwise or counterclockwise) around the high symmetry point, and the polar angle controls the magnitude of the spin polarization. These results are quite different from the situation where an external field is not applied to an electron in a crystal or where a classical external field is utilized to control the spin polarization of a photoemitted electron in a vacuum. Our results have potential applications in quantum optics and condensed-matter physics.
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24
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Iyer V, Chen YP, Xu X. Ultrafast Surface State Spin-Carrier Dynamics in the Topological Insulator Bi_{2}Te_{2}Se. PHYSICAL REVIEW LETTERS 2018; 121:026807. [PMID: 30085694 DOI: 10.1103/physrevlett.121.026807] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/06/2018] [Indexed: 06/08/2023]
Abstract
Topological insulators are promising candidates for optically driven spintronic devices, because photoexcitation of spin polarized surface states is governed by angular momentum selection rules. We carry out femtosecond midinfrared spectroscopy on thin films of the topological insulator Bi_{2}Te_{2}Se, which has a higher surface state conductivity compared to conventionally studied Bi_{2}Se_{3} and Bi_{2}Te_{3}. Both charge and spin dynamics are probed utilizing circularly polarized light. With a sub-band-gap excitation, clear helicity-dependent dynamics is observed only in thin (<20 nm) flakes. On the other hand, such dependence is observed for both thin and thick flakes with above-band-gap excitation. The helicity dependence is attributed to asymmetric excitation of the Dirac-like surface states. The observed long-lasting asymmetry over 10 ps even at room temperature indicates low backscattering of surface state carriers which can be exploited for spintronic devices.
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Affiliation(s)
- Vasudevan Iyer
- Department of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Yong P Chen
- Department of Physics and Astronomy and School of Electrical and Computer Engineering and Birck Nanotechnology Center and Purdue Quantum Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Xianfan Xu
- Department of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
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25
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Ishida Y, Shin S. Functions to map photoelectron distributions in a variety of setups in angle-resolved photoemission spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:043903. [PMID: 29716365 DOI: 10.1063/1.5007226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The distribution of photoelectrons acquired in angle-resolved photoemission spectroscopy can be mapped onto the energy-momentum space of the Bloch electrons in the crystal. The explicit forms of the mapping function f depend on the configuration of the apparatus as well as on the type of the photoelectron analyzer. We show that the existence of the analytic forms of f-1 is guaranteed in a variety of setups. The variety includes the case when the analyzer is equipped with a photoelectron deflector. Thereby, we provide a demonstrative mapping program implemented by an algorithm that utilizes both f and f-1. The mapping methodology is also usable in other spectroscopic methods such as momentum-resolved electron-energy loss spectroscopy.
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Affiliation(s)
- Y Ishida
- ISSP, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
| | - S Shin
- ISSP, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan
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26
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Bentmann H, Maaß H, Krasovskii EE, Peixoto TRF, Seibel C, Leandersson M, Balasubramanian T, Reinert F. Strong Linear Dichroism in Spin-Polarized Photoemission from Spin-Orbit-Coupled Surface States. PHYSICAL REVIEW LETTERS 2017; 119:106401. [PMID: 28949177 DOI: 10.1103/physrevlett.119.106401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Indexed: 06/07/2023]
Abstract
A comprehensive understanding of spin-polarized photoemission is crucial for accessing the electronic structure of spin-orbit coupled materials. Yet, the impact of the final state in the photoemission process on the photoelectron spin has been difficult to assess in these systems. We present experiments for the spin-orbit split states in a Bi-Ag surface alloy showing that the alteration of the final state with energy may cause a complete reversal of the photoelectron spin polarization. We explain the effect on the basis of ab initio one-step photoemission theory and describe how it originates from linear dichroism in the angular distribution of photoelectrons. Our analysis shows that the modulated photoelectron spin polarization reflects the intrinsic spin density of the surface state being sampled differently depending on the final state, and it indicates linear dichroism as a natural probe of spin-orbit coupling at surfaces.
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Affiliation(s)
- H Bentmann
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - H Maaß
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - E E Krasovskii
- Departamento de Física de Materiales, Facultad de Ciencias Quíimicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Apdo. 1072, San Sebastián/Donostia, 20080 Basque Country, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, San Sebastián/Donostia, 20018 Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - T R F Peixoto
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - C Seibel
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M Leandersson
- MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - T Balasubramanian
- MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - F Reinert
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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27
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Vasenko AS, Golubov AA, Silkin VM, Chulkov EV. Odd-frequency superconductivity induced in topological insulators with and without hexagonal warping. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:295502. [PMID: 28557795 DOI: 10.1088/1361-648x/aa75c3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We study the effect of the Fermi surface anisotropy on the odd-frequency spin-triplet pairing component of the induced pair potential. We consider a superconductor/ ferromagnetic insulator (S/FI) hybrid structure formed on the 3D topological insulator (TI) surface. In this case three ingredients ensure the possibility of the odd-frequency pairing: (1) the topological surface states, (2) the induced pair potential, and (3) the magnetic moment of a nearby ferromagnetic insulator. We take into account the strong anisotropy of the Dirac point in topological insulators when the chemical potential lies well above the Dirac cone and its constant energy contour has a snowflake shape. Within this model, we propose that the S/FI boundary should be properly aligned with respect to the snowflake constant energy contour to have an odd-frequency symmetry of the corresponding pairing component and to insure the Majorana bound state at the S/FI boundary. For arbitrary orientation of the boundary, the Majorana bound state is absent. This provides a selection rule to the realization of Majorana modes in S/FI hybrid structures, formed on the topological insulator surface.
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Affiliation(s)
- A S Vasenko
- National Research University Higher School of Economics, 101000 Moscow, Russia
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28
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Huang YQ, Song YX, Wang SM, Buyanova IA, Chen WM. Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator. Nat Commun 2017; 8:15401. [PMID: 28530227 PMCID: PMC5458147 DOI: 10.1038/ncomms15401] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 03/27/2017] [Indexed: 12/03/2022] Open
Abstract
A three-dimensional (3D) topological insulator (TI) is a unique quantum phase of matter with exotic physical properties and promising spintronic applications. However, surface spin current in a common 3D TI remains difficult to control and the out-of-plane spin texture is largely unexplored. Here, by means of surface spin photocurrent in Bi2Te3 TI devices driven by circular polarized light, we identify the subtle effect of the spin texture of the topological surface state including the hexagonal warping term on the surface current. By exploring the out-of-plane spin texture, we demonstrate spin injection from GaAs to TI and its significant contribution to the surface current, which can be manipulated by an external magnetic field. These discoveries pave the way to not only intriguing new physics but also enriched spin functionalities by integrating TI with conventional semiconductors, such that spin-enabled optoelectronic devices may be fabricated in such hybrid structures. Surface spin current in a 3D topological insulator (TI) remains difficult to control and the out-of-plane spin texture is largely unexplored. Here, the authors identify subtle effect of the spin texture on surface photocurrent and demonstrate controlled spin injection from a semiconductor to a TI.
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Affiliation(s)
- Y Q Huang
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 581 83, Sweden
| | - Y X Song
- State Key Laboratory of Functional Materials for Informatics, CAS Center of Excellence for Superconducting Electronics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - S M Wang
- State Key Laboratory of Functional Materials for Informatics, CAS Center of Excellence for Superconducting Electronics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China.,Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg 412 96, Sweden
| | - I A Buyanova
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 581 83, Sweden
| | - W M Chen
- Department of Physics, Chemistry and Biology, Linköping University, Linköping 581 83, Sweden
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29
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Arafune R, Nakazawa T, Takagi N, Kawai M, Ishida H. Comment on "Rashba Spin-Orbit Coupling in Image Potential States". PHYSICAL REVIEW LETTERS 2016; 117:239701. [PMID: 27982628 DOI: 10.1103/physrevlett.117.239701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Ryuichi Arafune
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Ibaraki 304-0044, Japan
| | - Takeo Nakazawa
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - Noriaki Takagi
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - Maki Kawai
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - Hiroshi Ishida
- College of Humanities and Sciences, Nihon University, Tokyo 156-8550, Japan
- Center for Materials Research by Information Integration, National Institute for Materials Science, Ibaraki 305-0047, Japan
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30
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Paaske J, Gaidamauskas E. Tunable Magnetic Anisotropy from Higher-Harmonics Exchange Scattering on the Surface of a Topological Insulator. PHYSICAL REVIEW LETTERS 2016; 117:177201. [PMID: 27824441 DOI: 10.1103/physrevlett.117.177201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Indexed: 06/06/2023]
Abstract
We show that higher-harmonics exchange scattering from a magnetic adatom on the surface of a three dimensional topological insulator leads to a magnetic anisotropy whose magnitude and sign may be tuned by adjusting the chemical potential of the helical surface band. As the chemical potential moves from the Dirac point towards the surface band edge, the surface normal is found to change from a magnetic easy to a hard axis. Hexagonal warping is shown to diminish the region with easy axis anisotropy, and to suppress the anisotropy altogether. This indirect contribution can be comparable in magnitude to the intrinsic term arising from crystal field splitting and atomic spin-orbit coupling, and its tunability with the chemical potential makes the two contributions experimentally discernible, and endows this source of anisotropy with potentially interesting magnetic functionality.
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Affiliation(s)
- Jens Paaske
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Erikas Gaidamauskas
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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31
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Surface Kondo effect and non-trivial metallic state of the Kondo insulator YbB12. Nat Commun 2016; 7:12690. [PMID: 27576449 PMCID: PMC5515356 DOI: 10.1038/ncomms12690] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/21/2016] [Indexed: 11/28/2022] Open
Abstract
A synergistic effect between strong electron correlation and spin–orbit interaction has been theoretically predicted to realize new topological states of quantum matter on Kondo insulators (KIs), so-called topological Kondo insulators (TKIs). One TKI candidate has been experimentally observed on the KI SmB6(001), and the origin of the surface states (SS) and the topological order of SmB6 has been actively discussed. Here, we show a metallic SS on the clean surface of another TKI candidate YbB12(001) using angle-resolved photoelectron spectroscopy. The SS shows temperature-dependent reconstruction corresponding to the Kondo effect observed for bulk states. Despite the low-temperature insulating bulk, the reconstructed SS with c–f hybridization is metallic, forming a closed Fermi contour surrounding on the surface Brillouin zone and agreeing with the theoretically expected behaviour for SS on TKIs. These results demonstrate the temperature-dependent holistic reconstruction of two-dimensional states localized on KIs surface driven by the Kondo effect. Topological state in Kondo insulators has been provoked in SmB6, but the origin of surface states and topological order remain elusive. Here, Hagiwara et al. report temperature dependent reconstruction of a metallic surface state on the (001) surface of YbB12 driven by Kondo effect and discuss its origin from topology.
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32
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Bera A, Pal K, Muthu DVS, Waghmare UV, Sood AK. Pressure-induced phase transition in Bi2Se3 at 3 GPa: electronic topological transition or not? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:105401. [PMID: 26881905 DOI: 10.1088/0953-8984/28/10/105401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In recent years, a low pressure transition around P3 GPa exhibited by the A2B3-type 3D topological insulators is attributed to an electronic topological transition (ETT) for which there is no direct evidence either from theory or experiments. We address this phase transition and other transitions at higher pressure in bismuth selenide (Bi2Se3) using Raman spectroscopy at pressure up to 26.2 GPa. We see clear Raman signatures of an isostructural phase transition at P2.4 GPa followed by structural transitions at ∼ 10 GPa and 16 GPa. First-principles calculations reveal anomalously sharp changes in the structural parameters like the internal angle of the rhombohedral unit cell with a minimum in the c/a ratio near P3 GPa. While our calculations reveal the associated anomalies in vibrational frequencies and electronic bandgap, the calculated Z2 invariant and Dirac conical surface electronic structure remain unchanged, showing that there is no change in the electronic topology at the lowest pressure transition.
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Affiliation(s)
- Achintya Bera
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
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33
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Sorb YA, Rajaji V, Malavi PS, Subbarao U, Halappa P, Peter SC, Karmakar S, Narayana C. Pressure-induced electronic topological transition in Sb2S3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:015602. [PMID: 26656791 DOI: 10.1088/0953-8984/28/1/015602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the high-pressure vibrational properties and a pressure-induced electronic topological transition in the wide bandgap semiconductor Sb2S3 (E g = 1.7-1.8 eV) using Raman spectroscopy, resistivity and x-ray diffraction (XRD) studies. In this report, high-pressure Raman spectroscopy and resistivity studies of Sb2S3 have been carried out to 22 GPa and 11 GPa, respectively. We observed the softening of phonon modes [Formula: see text], [Formula: see text] and B 2g and a sharp anomaly in their line widths at 4 GPa. The resistivity studies corroborate this anomaly around similar pressures. The changes in resistivity as well as Raman line widths can be ascribed to the strong phonon-phonon coupling, indicating clear evidence of isostructural electronic topological transition in Sb2S3. The previously reported pressure dependence of a/c ratio plot obtained also showed a minimum at ~5 GPa consistent with our high-pressure Raman and resistivity results.
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Affiliation(s)
- Y A Sorb
- Chemistry and Physics of Materials Unit, JNCASR, Jakkur, Bangalore 560 064, India
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34
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Krasovskii EE. Spin-orbit coupling at surfaces and 2D materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:493001. [PMID: 26580290 DOI: 10.1088/0953-8984/27/49/493001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Spin-orbit interaction gives rise to a splitting of surface states via the Rashba effect, and in topological insulators it leads to the existence of topological surface states. The resulting k(//) momentum separation between states with the opposite spin underlies a wide range of new phenomena at surfaces and interfaces, such as spin transfer, spin accumulation, spin-to-charge current conversion, which are interesting for fundamental science and may become the basis for a breakthrough in the spintronic technology. The present review summarizes recent theoretical and experimental efforts to reveal the microscopic structure and mechanisms of spin-orbit driven phenomena with the focus on angle and spin-resolved photoemission and scanning tunneling microscopy.
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Affiliation(s)
- E E Krasovskii
- Departamento de Física de Materiales, Universidad del Pais Vasco UPV/EHU, 20080 San Sebastián/Donostia, Spain. Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain. IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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35
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Schmeltzer D, Saxena A. Surface state photoelectrons in topological insulators: Green's function approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:485601. [PMID: 26565417 DOI: 10.1088/0953-8984/27/48/485601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We compute the photoemission intensity and polarization for the surface states in topological insulators. Due to the chirality and linear energy dispersion the effective electron-photon coupling is normalized by the tunneling amplitude (τ) into the vacuum. We investigate a chiral Dirac Hamiltonian for different cases: helical, Zeeman and warping, allowing us to study spin textures. Using the Green's function formalism we obtain exact results for the emitted photoelectrons to second order in the laser field. The number of emitted photoelectrons is sensitive to the laser coherent state intensity whereas the photoelectron polarization is sensitive to the surface topology of electronic states and incoming photon polarization.
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Affiliation(s)
- D Schmeltzer
- Physics Department, City College of the City University of New York, NY 10031, USA
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36
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Jiang J, Tang F, Pan XC, Liu HM, Niu XH, Wang YX, Xu DF, Yang HF, Xie BP, Song FQ, Dudin P, Kim TK, Hoesch M, Das PK, Vobornik I, Wan XG, Feng DL. Signature of Strong Spin-Orbital Coupling in the Large Nonsaturating Magnetoresistance Material WTe2. PHYSICAL REVIEW LETTERS 2015; 115:166601. [PMID: 26550888 DOI: 10.1103/physrevlett.115.166601] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 06/05/2023]
Abstract
We report the detailed electronic structure of WTe2 by high resolution angle-resolved photoemission spectroscopy. We resolved a rather complicated Fermi surface of WTe2. Specifically, there are in total nine Fermi pockets, including one hole pocket at the Brillouin zone center Γ, and two hole pockets and two electron pockets on each side of Γ along the Γ-X direction. Remarkably, we have observed circular dichroism in our photoemission spectra, which suggests that the orbital angular momentum exhibits a rich texture at various sections of the Fermi surface. This is further confirmed by our density-functional-theory calculations, where the spin texture is qualitatively reproduced as the conjugate consequence of spin-orbital coupling. Since the spin texture would forbid backscatterings that are directly involved in the resistivity, our data suggest that the spin-orbit coupling and the related spin and orbital angular momentum textures may play an important role in the anomalously large magnetoresistance of WTe2. Furthermore, the large differences among spin textures calculated for magnetic fields along the in-plane and out-of-plane directions also provide a natural explanation of the large field-direction dependence on the magnetoresistance.
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Affiliation(s)
- J Jiang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Tang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X C Pan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - H M Liu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Y X Wang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - D F Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - H F Yang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Q Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - P Kumar Das
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
- International Centre for Theoretical Physics, Strada Costiera 11, 34100 Trieste, Italy
| | - I Vobornik
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
| | - X G Wan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
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37
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Sengupta P, Bellotti E. Scattering times and surface conductivity of Dirac fermions in a 3D topological insulator film with localised impurities. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:405301. [PMID: 26402336 DOI: 10.1088/0953-8984/27/40/405301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The zero gap surface states of a 3D-topological insulator host highly mobile Dirac fermions with spin locked to the momentum. The high mobility attributed to the absence of back scattering is reduced in the presence of impurities on the surface. In particular, we discuss and compare scattering times for localised impurities on the surface, scattering between states of opposite helicity located on different surfaces coupled through a hybridisation potential and the role of magnetic impurities. Magnetic impurities give rise to an additional spin suppression factor. The role of warped bands and their influence on topological factors that can enhance the overall surface mobility is examined. Finally, employing a linearised Boltzmann equation approach, surface conductivity calculations for Dirac fermions in a 3D TI is outlined.
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Affiliation(s)
- Parijat Sengupta
- Department of Electrical and Computer Engineering, Boston University, 8 St. Mary's Street, Boston, MA 02215, USA
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Bawden L, Riley JM, Kim CH, Sankar R, Monkman EJ, Shai DE, Wei HI, Lochocki EB, Wells JW, Meevasana W, Kim TK, Hoesch M, Ohtsubo Y, Le Fèvre P, Fennie CJ, Shen KM, Chou F, King PDC. Hierarchical spin-orbital polarization of a giant Rashba system. SCIENCE ADVANCES 2015; 1:e1500495. [PMID: 26601268 PMCID: PMC4643772 DOI: 10.1126/sciadv.1500495] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/16/2015] [Indexed: 06/02/2023]
Abstract
The Rashba effect is one of the most striking manifestations of spin-orbit coupling in solids and provides a cornerstone for the burgeoning field of semiconductor spintronics. It is typically assumed to manifest as a momentum-dependent splitting of a single initially spin-degenerate band into two branches with opposite spin polarization. Combining polarization-dependent and resonant angle-resolved photoemission measurements with density functional theory calculations, we show that the two "spin-split" branches of the model giant Rashba system BiTeI additionally develop disparate orbital textures, each of which is coupled to a distinct spin configuration. This necessitates a reinterpretation of spin splitting in Rashba-like systems and opens new possibilities for controlling spin polarization through the orbital sector.
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Affiliation(s)
- Lewis Bawden
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, UK
| | - Jonathan M. Riley
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, UK
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - Choong H. Kim
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Raman Sankar
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Eric J. Monkman
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Daniel E. Shai
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Haofei I. Wei
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Edward B. Lochocki
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - Justin W. Wells
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway
| | - Worawat Meevasana
- School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
- NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Timur K. Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - Moritz Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - Yoshiyuki Ohtsubo
- Synchrotron SOLEIL, CNRS-CEA, L’Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - Patrick Le Fèvre
- Synchrotron SOLEIL, CNRS-CEA, L’Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
| | - Craig J. Fennie
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Kyle M. Shen
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA
| | - Fangcheng Chou
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Phil D. C. King
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, UK
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Wang YH, Kirtley JR, Katmis F, Jarillo-Herrero P, Moodera JS, Moler KA. RETRACTED: Observation of chiral currents at the magnetic domain boundary of a topological insulator. Science 2015; 349:948-52. [PMID: 26272905 DOI: 10.1126/science.aaa0508] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 07/29/2015] [Indexed: 02/23/2024]
Abstract
A magnetic domain boundary on the surface of a three-dimensional topological insulator is predicted to host a chiral edge state, but direct demonstration is challenging. We used a scanning superconducting quantum interference device to show that current in a magnetized topological insulator heterostructure (EuS/Bi2Se3) flows at the edge when the Fermi level is gate-tuned to the surface band gap. We further induced micrometer-scale magnetic structures on the heterostructure and detected a chiral edge current at the magnetic domain boundary. The chirality of the current was determined by magnetization of the surrounding domain, and its magnitude by the local chemical potential rather than the applied current. Such magnetic structures provide a platform for detecting topological magnetoelectric effects and may enable progress in quantum information processing and spintronics.
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Affiliation(s)
- Y H Wang
- Department of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
| | - J R Kirtley
- Department of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - F Katmis
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - P Jarillo-Herrero
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J S Moodera
- Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - K A Moler
- Department of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
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Sengupta P, Klimeck G, Bellotti E. The evaluation of non-topological components in Berry phase and momentum relaxation time in a gapped 3D topological insulator. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:335505. [PMID: 26241517 DOI: 10.1088/0953-8984/27/33/335505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The zero gap surface states of a 3D-topological insulator host Dirac fermions with spin locked to the momentum. The gap-less Dirac fermions exhibit electronic behaviour different from those predicted in conventional materials. While calculations based on a simple linear dispersion can account for observed experimental patterns, a more accurate description of the physics of these systems and a better agreement between experimental data theoretical results can be obtained by including higher order k terms in the Hamiltonian. In this work, in presence of a time reversal symmetry breaking external magnetic field and higher order warping term, alteration to the topologically ordained Berry phase of (2n + 1)π, momentum relaxation time, and the magneto-conductivity tensors is established. The relation between scattering times and the deviations to topological Berry phase of π is also emphasized.
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Affiliation(s)
- Parijat Sengupta
- Department of Electrical and Computer Engineering and Material Science Division, Boston University, Boston, MA 02215, USA
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41
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Xu CZ, Liu Y, Yukawa R, Zhang LX, Matsuda I, Miller T, Chiang TC. Photoemission Circular Dichroism and Spin Polarization of the Topological Surface States in Ultrathin Bi2Te3 Films. PHYSICAL REVIEW LETTERS 2015; 115:016801. [PMID: 26182112 DOI: 10.1103/physrevlett.115.016801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Indexed: 06/04/2023]
Abstract
Circular dichroism (CD) observed by photoemission, being sensitive to the orbital and spin angular momenta of the electronic states, is a powerful probe of the nontrivial surface states of topological insulators, but the experimental results thus far have eluded a comprehensive description. We report a study of Bi2Te3 films with thicknesses ranging from one quintuple layer (two-dimensional limit) to 12 layers (bulk limit) over a wide range of incident photon energy. The data show complex variations in magnitude and sign reversals, which are nevertheless well described by a theoretical calculation including all three photoemission mechanisms: dipole transition, surface photoemission, and spin-orbit coupling. The results establish the nontrivial connection between the spin-orbit texture and CD.
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Affiliation(s)
- C-Z Xu
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Y Liu
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- X-ray science division, Argonne National Lab, 9700 South Cass Avenue, Lemont, Illinois 60439, USA
| | - R Yukawa
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - L-X Zhang
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - I Matsuda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T Miller
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - T-C Chiang
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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42
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Contact effects in thin 3D-topological insulators: how does the current flow? Sci Rep 2015; 5:9479. [PMID: 25820460 PMCID: PMC4377578 DOI: 10.1038/srep09479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/23/2015] [Indexed: 11/08/2022] Open
Abstract
The effect of different contact configurations (semi-infinite extended-channel, normal metal and ferromagnetic metal) on quantum transport through thin Bi2Se3 three-dimensional (3D) topological insulator (TI) slab (channel) has been investigated through Non-Equilibrium Green Function. The issue of contact dependent current flow and distribution across quintuple layers of 3D-TI has been addressed in this work and applied to expound the explanation for recent experimental work on electrical detection of spin-momentum locking on topological surface for long channel device. A theoretical model is propounded to develop a microscopic understanding of transport in 3D-TI in which contact type and magnetization concur with helical surface states of the TI channel to manifest seemingly counter-intuitive current distribution across layers. The quantum transport calculations for short channel devices with magnetic source and drain contacts postulate negative surface current for anti-phase magnetization whose axis is transverse to both current and quintuple layers. For in-phase magnetization at the two terminals, it is shown that observations can change fundamentally to result in anomalous current distribution. Such results are explained to stem from the confinement of 3D-TI between ferromagnetic contacts along the transport direction. A simple mechanism to validate topological insulators via quantum transport experiments has also been suggested.
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Kastl C, Karnetzky C, Karl H, Holleitner AW. Ultrafast helicity control of surface currents in topological insulators with near-unity fidelity. Nat Commun 2015; 6:6617. [PMID: 25808213 PMCID: PMC4389261 DOI: 10.1038/ncomms7617] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 02/11/2015] [Indexed: 12/24/2022] Open
Abstract
In recent years, a class of solid-state materials, called three-dimensional topological insulators, has emerged. In the bulk, a topological insulator behaves like an ordinary insulator with a band gap. At the surface, conducting gapless states exist showing remarkable properties such as helical Dirac dispersion and suppression of backscattering of spin-polarized charge carriers. The characterization and control of the surface states via transport experiments is often hindered by residual bulk contributions. Here we show that surface currents in Bi2Se3 can be controlled by circularly polarized light on a picosecond timescale with a fidelity near unity even at room temperature. We reveal the temporal separation of such ultrafast helicity-dependent surface currents from photo-induced thermoelectric and drift currents in the bulk. Our results uncover the functionality of ultrafast optoelectronic devices based on surface currents in topological insulators. Bulk contributions to transport measurements often inhibit the study of the surface states of topological insulators. Here, Kastl et al. demonstrate high-fidelity helicity-dependent photocurrents in the surface states of Bi2Se3, controlled via circularly polarized light with a picosecond time-resolution.
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Affiliation(s)
- Christoph Kastl
- 1] Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4a, 85748 Garching, Germany [2] Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 München, Germany
| | - Christoph Karnetzky
- 1] Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4a, 85748 Garching, Germany [2] Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 München, Germany
| | - Helmut Karl
- Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
| | - Alexander W Holleitner
- 1] Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4a, 85748 Garching, Germany [2] Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 München, Germany
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Yan Y, Liao ZM, Ke X, Van Tendeloo G, Wang Q, Sun D, Yao W, Zhou S, Zhang L, Wu HC, Yu DP. Topological surface state enhanced photothermoelectric effect in Bi2Se3 nanoribbons. NANO LETTERS 2014; 14:4389-94. [PMID: 25046135 DOI: 10.1021/nl501276e] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The photothermoelectric effect in topological insulator Bi2Se3 nanoribbons is studied. The topological surface states are excited to be spin-polarized by circularly polarized light. Because the direction of the electron spin is locked to its momentum for the spin-helical surface states, the photothermoelectric effect is significantly enhanced as the oriented motions of the polarized spins are accelerated by the temperature gradient. The results are explained based on the microscopic mechanisms of a photon induced spin transition from the surface Dirac cone to the bulk conduction band. The as-reported enhanced photothermoelectric effect is expected to have potential applications in a spin-polarized power source.
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Affiliation(s)
- Yuan Yan
- State Key Laboratory for Mesoscopic Physics, Department of Physics and ∥International Center for Quantum Materials, Peking University , Beijing 100871, P. R. China
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45
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Xia M, Jiang J, Ye ZR, Wang YH, Zhang Y, Chen SD, Niu XH, Xu DF, Chen F, Chen XH, Xie BP, Zhang T, Feng DL. Angle-resolved photoemission spectroscopy study on the surface states of the correlated topological insulator YbB6. Sci Rep 2014; 4:5999. [PMID: 25102781 PMCID: PMC4126005 DOI: 10.1038/srep05999] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 07/21/2014] [Indexed: 11/27/2022] Open
Abstract
YbB6 is recently predicted to be a moderately correlated topological insulator, which provides a playground to explore the interplay between correlation and topological properties. With angle-resolved photoemission spectroscopy, we directly observed almost linearly dispersive bands around the time-reversal invariant momenta and with negligible kz dependence, consistent with odd number of surface states crossing the Fermi level in a Z2 topological insulator. Circular dichroism photoemission spectra suggest that these in-gap states possess chirality of orbital angular momentum, which is related to the chiral spin texture, further indicative of their topological nature. The observed insulating gap of YbB6 is about 100 meV, larger than that found by theoretical calculations. Our results present strong evidence that YbB6 is a correlated topological insulator and provide a foundation for further studies of this promising material.
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Affiliation(s)
- M Xia
- 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2]
| | - J Jiang
- 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2]
| | - Z R Ye
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Y H Wang
- Department of Physics and Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Y Zhang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - S D Chen
- Department of Physics and Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - D F Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - F Chen
- Department of Physics and Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - X H Chen
- Department of Physics and Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - T Zhang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
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46
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Jiang J, Li S, Zhang T, Sun Z, Chen F, Ye ZR, Xu M, Ge QQ, Tan SY, Niu XH, Xia M, Xie BP, Li YF, Chen XH, Wen HH, Feng DL. Observation of possible topological in-gap surface states in the Kondo insulator SmB6 by photoemission. Nat Commun 2014; 4:3010. [PMID: 24346657 PMCID: PMC3905704 DOI: 10.1038/ncomms4010] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 11/26/2013] [Indexed: 11/13/2022] Open
Abstract
SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states. The Kondo insulator samarium hexaboride exhibits low-temperature transport anomalies, which might be due to topological surface states. Here Jiang et al. perform angle-resolved photoemission and its circular dichroism measurements, which suggest that the anomalies might be of topological origin.
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Affiliation(s)
- J Jiang
- 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2]
| | - S Li
- 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2]
| | - T Zhang
- 1] State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China [2]
| | - Z Sun
- 1] Department of Physics, University of Science and Technology of China, Hefei 230026, China [2] National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - F Chen
- Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Z R Ye
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - M Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Q Q Ge
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - S Y Tan
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - M Xia
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
| | - Y F Li
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - X H Chen
- 1] Department of Physics, University of Science and Technology of China, Hefei 230026, China [2] Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - H H Wen
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
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47
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Identification of helicity-dependent photocurrents from topological surface states in Bi2Se3 gated by ionic liquid. Sci Rep 2014; 4:4889. [PMID: 24809330 PMCID: PMC4013928 DOI: 10.1038/srep04889] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 04/16/2014] [Indexed: 11/17/2022] Open
Abstract
Dirac-like surface states on surfaces of topological insulators have a chiral spin structure with spin locked to momentum, which is interesting in physics and may also have important applications in spintronics. In this work, by measuring the tunable helicity-dependent photocurrent (HDP), we present an identification of the HDP from the Dirac-like surface states at room temperature. It turns out that the total HDP has two components, one from the Dirac-like surface states, and the other from the surface accumulation layer. These two components have opposite directions. The clear gate tuning of the electron density as well as the HDP signal indicates that the surface band bending and resulted surface accumulation are successfully modulated by the applied ionic liquid gate, which provides a promising way to the study of the Dirac-like surface states and also potential applications in spintronic devices.
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48
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Zhu ZH, Veenstra CN, Zhdanovich S, Schneider MP, Okuda T, Miyamoto K, Zhu SY, Namatame H, Taniguchi M, Haverkort MW, Elfimov IS, Damascelli A. Photoelectron spin-polarization control in the topological insulator Bi2Se3. PHYSICAL REVIEW LETTERS 2014; 112:076802. [PMID: 24579623 DOI: 10.1103/physrevlett.112.076802] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Indexed: 06/03/2023]
Abstract
We study the manipulation of the spin polarization of photoemitted electrons in Bi2Se3 by spin- and angle-resolved photoemission spectroscopy. General rules are established that enable controlling the photoelectron spin-polarization. We demonstrate the ± 100% reversal of a single component of the measured spin-polarization vector upon the rotation of light polarization, as well as full three-dimensional manipulation by varying experimental configuration and photon energy. While a material-specific density-functional theory analysis is needed for the quantitative description, a minimal yet fully generalized two-atomic-layer model qualitatively accounts for the spin response based on the interplay of optical selection rules, photoelectron interference, and topological surface-state complex structure. It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture.
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Affiliation(s)
- Z-H Zhu
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - C N Veenstra
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - S Zhdanovich
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - M P Schneider
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - T Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - K Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - S-Y Zhu
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - H Namatame
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - M Taniguchi
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan and Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - M W Haverkort
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany and Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - I S Elfimov
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada and Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - A Damascelli
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada and Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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49
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Ohtsubo Y, Le Fèvre P, Bertran F, Taleb-Ibrahimi A. Dirac cone with helical spin polarization in ultrathin α-Sn(001) films. PHYSICAL REVIEW LETTERS 2013; 111:216401. [PMID: 24313507 DOI: 10.1103/physrevlett.111.216401] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 09/19/2013] [Indexed: 06/02/2023]
Abstract
Spin-split two-dimensional electronic states have been observed on ultrathin Sn(001) films grown on InSb(001) substrates. Angle-resolved photoelectron spectroscopy (ARPES) performed on these films revealed Dirac-cone-like linear dispersion around the Γ¯ point of the surface Brillouin zone, suggesting nearly massless electrons belonging to 2D surface states. The states disperse across a band gap between bulklike quantum well states in the films. Moreover, both circular dichroism of ARPES and spin-resolved ARPES studies show helical spin polarization of the Dirac-cone-like surface states, suggesting a topologically protected character as in a bulk topological insulator (TI). These results indicate that a quasi-3D TI phase can be realized in ultrathin films of zero-gap semiconductors.
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Affiliation(s)
- Yoshiyuki Ohtsubo
- Synchrotron SOLEIL, Saint-Aubin-BP 48, F-91192 Gif sur Yvette, France
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50
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Wang YH, Steinberg H, Jarillo-Herrero P, Gedik N. Observation of Floquet-Bloch states on the surface of a topological insulator. Science 2013; 342:453-7. [PMID: 24159040 DOI: 10.1126/science.1239834] [Citation(s) in RCA: 237] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The unique electronic properties of the surface electrons in a topological insulator are protected by time-reversal symmetry. Circularly polarized light naturally breaks time-reversal symmetry, which may lead to an exotic surface quantum Hall state. Using time- and angle-resolved photoemission spectroscopy, we show that an intense ultrashort midinfrared pulse with energy below the bulk band gap hybridizes with the surface Dirac fermions of a topological insulator to form Floquet-Bloch bands. These photon-dressed surface bands exhibit polarization-dependent band gaps at avoided crossings. Circularly polarized photons induce an additional gap at the Dirac point, which is a signature of broken time-reversal symmetry on the surface. These observations establish the Floquet-Bloch bands in solids and pave the way for optical manipulation of topological quantum states of matter.
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Affiliation(s)
- Y H Wang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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