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Wu M, Tu D, Nie Y, Miao S, Gao W, Han Y, Zhu X, Zhou J, Ning W, Tian M. Novel π/2-Periodic Planar Hall Effect Due to Orbital Magnetic Moments in MnBi 2Te 4. NANO LETTERS 2022; 22:73-80. [PMID: 34962398 DOI: 10.1021/acs.nanolett.1c03232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The Berry curvature and orbital magnetic moment (OMM) come from either inversion symmetry or time-reversal symmetry breaking in quantum materials. Here, we demonstrate the significance of OMMs and Berry curvature in planar Hall effect (PHE) in antiferromagnetic topological insulator MnBi2Te4 flakes. We observe a PHE with period of π and positive magnitude at low fields, resembling the PHE of the surface states in nonmagnetic topological insulators. Remarkably, a novel predominant PHE with period of π/2 and negative magnitude emerges below the Néel temperature with B > 10 T. Our theoretical calculations reveal that this unusual π/2-periodic PHE originates from the topological OMMs of bulk Dirac electrons. Moreover, the competition between the contributions from the bulk and the surface states leads to nontrivial evolutions of PHE and anisotropic magnetoresistance. Our results reveal intriguing electromagnetic response due to the OMMs and also provide insight into the potential applications of magnetic topological insulators in spintronics.
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Affiliation(s)
- Min Wu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
| | - Daifeng Tu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
- Department of Physics, University of Science and Technology of China, Hefei 230026, P.R. China
| | - Yong Nie
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
- Department of Physics, University of Science and Technology of China, Hefei 230026, P.R. China
| | - Shaopeng Miao
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
- Department of Physics, University of Science and Technology of China, Hefei 230026, P.R. China
| | - Wenshuai Gao
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei 230601, P.R. China
| | - Yuyan Han
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
| | - Xiangde Zhu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
| | - Jianhui Zhou
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
| | - Wei Ning
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
| | - Mingliang Tian
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei 230601, P.R. China
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52
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Zang Z, Zhu Y, Xi M, Tian S, Wang T, Gu P, Peng Y, Yang S, Xu X, Li Y, Han B, Liu L, Wang Y, Gao P, Yang J, Lei H, Huang Y, Ye Y. Layer-Number-Dependent Antiferromagnetic and Ferromagnetic Behavior in MnSb_{2}Te_{4}. PHYSICAL REVIEW LETTERS 2022; 128:017201. [PMID: 35061452 DOI: 10.1103/physrevlett.128.017201] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/25/2021] [Accepted: 11/29/2021] [Indexed: 05/23/2023]
Abstract
MnBi_{2}Te_{4}, an intrinsic magnetic topological insulator, has shown layer-number-correlated magnetic and topological phases. More interestingly, in the isostructural material MnSb_{2}Te_{4}, the antiferromagnetic (AFM) and ferromagnetic (FM) states have been both observed in the bulk counterparts, which are also predicted to be topologically nontrivial. Revealing the layer-number-dependent magnetic properties of MnSb_{2}Te_{4} down to a single septuple layer (SL) is of great significance for exploring the topological phenomena. However, this is still elusive. Here, using the polar reflective magnetic circular dichroism spectroscopy, both the A-type AFM and FM behaviors are observed and comprehensively studied in MnSb_{2}Te_{4} down to a single SL limit. In A-type AFM MnSb_{2}Te_{4} flakes, an obvious odd-even layer-number effect is observed. An additional surface spin-flop (SSF) transition occurs in even-SL flakes with the number of layers larger than 2. With the AFM linear-chain model, we identify that the even-SL flakes stabilize in a collinear state between the SSF transition and the spin-flop transition due to their appropriate energy ratio between the magnetic-field-scale anisotropy and interlayer interaction. In FM MnSb_{2}Te_{4} flakes, we observe very different magnetic behaviors with an abrupt spin-flipping transition and very small saturation fields, indicating a weakened interlayer interaction. By revealing the rich magnetic states of few-SL MnSb_{2}Te_{4} on the parameter space of the number of layers, external magnetic field, and temperature, our findings pave the way for further quantum transport studies of few-SL MnSb_{2}Te_{4}.
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Affiliation(s)
- Zhihao Zang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yaozheng Zhu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Ming Xi
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
| | - Shangjie Tian
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
| | - Tingting Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Pingfan Gu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yuxuan Peng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Shiqi Yang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xiaolong Xu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yanping Li
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Bo Han
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Liwei Liu
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yeliang Wang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Peng Gao
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
| | - Jinbo Yang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
| | - Yuan Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yu Ye
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing 100871, China
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53
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Huang B, Yang X, Zhang Q, Xu N. Chiral Majorana edge modes and vortex Majorana zero modes in superconducting antiferromagnetic topological insulator. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:115503. [PMID: 34933290 DOI: 10.1088/1361-648x/ac4531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The antiferromagnetic topological insulator (AFTI) is topologically protected by the combined time-reversal and translational symmetryTc. In this paper we investigate the effects of thes-wave superconducting pairings on the multilayers of AFTI, which breaksTcsymmetry and can realize quantum anomalous Hall insulator with unit Chern number. For the weakly coupled pairings, the system corresponds to the topological superconductor (TSC) with the Chern numberC= ±2. We answer the following questions whether the local Chern numbers and chiral Majorana edge modes of such a TSC distribute around the surface layers. By the numerical calculations based on a theoretic model of AFTI, we find that when the local Chern numbers are always dominated by the surface layers, the wavefunctions of chiral Majorana edge modes must not localize on the surface layers and show a smooth crossover from spatially occupying all layers to only distributing near the surface layers, similar to the hinge states in a three dimensional second-order topological phases. The latter phase, denoted by the hinged TSC, can be distinguished from the former phase by the measurements of the local density of state. In addition we also study the superconducting vortex phase transition in this system and find that the exchange field in the AFTI not only enlarges the phase space of topological vortex phase but also enhances its topological stability. These conclusions will stimulate the investigations on superconducting effects of AFTI and drive the studies on chiral Majorana edge modes and vortex Majorana zero modes into a new era.
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Affiliation(s)
- Beibing Huang
- Department of Physics, Yancheng Institute of Technology, Yancheng, 224051, People's Republic of China
| | - Xiaosen Yang
- Department of physics, Jiangsu University, Zhenjiang, 212013, People's Republic of China
| | - Qinfang Zhang
- School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, People's Republic of China
| | - Ning Xu
- Department of Physics, Yancheng Institute of Technology, Yancheng, 224051, People's Republic of China
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54
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Li H, Chen CZ, Jiang H, Xie XC. Coexistence of Quantum Hall and Quantum Anomalous Hall Phases in Disordered MnBi_{2}Te_{4}. PHYSICAL REVIEW LETTERS 2021; 127:236402. [PMID: 34936771 DOI: 10.1103/physrevlett.127.236402] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
In most cases, to observe quantized Hall plateaus, an external magnetic field is applied in intrinsic magnetic topological insulators MnBi_{2}Te_{4}. Nevertheless, whether the nonzero Chern number (C≠0) phase is a quantum anomalous Hall (QAH) state, or a quantum Hall (QH) state, or a mixing state of both is still a puzzle, especially for the recently observed C=2 phase [Deng et al., Science 367, 895 (2020)SCIEAS0036-807510.1126/science.aax8156]. In this Letter, we propose a physical picture based on the Anderson localization to understand the observed Hall plateaus in disordered MnBi_{2}Te_{4}. Rather good consistency between the experimental and numerical results confirms that the bulk states are localized in the absence of a magnetic field and a QAH edge state emerges with C=1. However, under a strong magnetic field, the lowest Landau band formed with the localized bulk states, survives disorder, together with the QAH edge state, leading to a C=2 phase. Eventually, we present a phase diagram of a disordered MnBi_{2}Te_{4} which indicates more coexistence states of QAH and QH to be verified by future experiments.
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Affiliation(s)
- Hailong Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Chui-Zhen Chen
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
- Institute for Advanced Study, Soochow University, Suzhou 215006, China
| | - Hua Jiang
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
- Institute for Advanced Study, Soochow University, Suzhou 215006, China
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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55
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Petrov EK, Ernst A, Menshchikova TV, Chulkov EV. Intrinsic Magnetic Topological Insulator State Induced by the Jahn-Teller Effect. J Phys Chem Lett 2021; 12:9076-9085. [PMID: 34516740 DOI: 10.1021/acs.jpclett.1c02396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Jahn-Teller effect is a geometrical distortion which lowers the system symmetry and lifts orbital degeneracy in molecules and solids. It affects a wide range of properties, including magnetic and band structures. In this work we propose a family of Cr-containing intrinsic magnetic topological insulator materials which are subjected to a pseudo-Jahn-Teller effect-CrBi2Se4, CrBi2Te2Se2, and CrBi2Te4. Using first-principles calculations we study their properties and investigate the impact of Jahn-Teller distortions on the electronic and magnetic properties. We show that these distortions can significantly affect magnetic anisotropy energy and band structure. Without the distortions accounted for, all three of the compounds exhibit a semimetallic band structure. The distortions open a band gap, which in the cases of CrBi2Te2Se2 and CrBi2Te4 is inverted. We also investigate the CrBi2Te2Se2 and CrBi2Te4 surface band structure and demonstrate that the surface states have a topological origin.
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Affiliation(s)
- E K Petrov
- Tomsk State University, Tomsk, 634050 Russia
- St. Petersburg State University, St. Petersburg, 199034 Russia
| | - A Ernst
- Institute for Theoretical Physics, Johannes Kepler University, 4040 Linz, Austria
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | | | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain
- St. Petersburg State University, St. Petersburg, 199034 Russia
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56
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Zhao YF, Zhou LJ, Wang F, Wang G, Song T, Ovchinnikov D, Yi H, Mei R, Wang K, Chan MHW, Liu CX, Xu X, Chang CZ. Even-Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi 2Te 4 Thin Films. NANO LETTERS 2021; 21:7691-7698. [PMID: 34468149 DOI: 10.1021/acs.nanolett.1c02493] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recently, MnBi2Te4 has been demonstrated to be an intrinsic magnetic topological insulator and the quantum anomalous Hall (QAH) effect was observed in exfoliated MnBi2Te4 flakes. Here, we used molecular beam epitaxy (MBE) to grow MnBi2Te4 films with thickness down to 1 septuple layer (SL) and performed thickness-dependent transport measurements. We observed a nonsquare hysteresis loop in the antiferromagnetic state for films with thickness greater than 2 SL. The hysteresis loop can be separated into two AH components. We demonstrated that one AH component with the larger coercive field is from the dominant MnBi2Te4 phase, whereas the other AH component with the smaller coercive field is from the minor Mn-doped Bi2Te3 phase. The extracted AH component of the MnBi2Te4 phase shows a clear even-odd layer-dependent behavior. Our studies reveal insights on how to optimize the MBE growth conditions to improve the quality of MnBi2Te4 films.
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Affiliation(s)
- Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ling-Jie Zhou
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Fei Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Guang Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tiancheng Song
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Dmitry Ovchinnikov
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Hemian Yi
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ruobing Mei
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ke Wang
- Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chao-Xing Liu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
- Department of Material Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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57
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Li P, You Y, Huang K, Luo W. Quantum anomalous Hall effect in Cr 2Ge 2Te 6/Bi 2Se 3/Cr 2Ge 2Te 6heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:465003. [PMID: 34433141 DOI: 10.1088/1361-648x/ac2117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Currently, quantum anomalous Hall (QAH) effect can only be observed at very low temperatures, which severely hinders its utilization from spintronics to quantum computation. Finding or predicting new systems supporting QAH effect at high temperatures remains essential and challenging. This work presents first-principles studies on the proximity effect between Bi2Se3slabs and Cr2Ge2Te6(CGT) layers, reporting that Chern insulators are available in CGT/Bi2Se3/CGT heterostructures. If the sandwiched Bi2Se3slab is 4 quintuple layers (QLs) or thicker, the Chern insulating state is robust against the interfacial stacking manner. If the Bi2Se3slab is only 2 or 3 QLs, the CrBi- and CrH-aligned heterostructures are also Chern insulators, while the CrSe-aligned ones are trivial. The Chern insulators support the Hall conductivityσxy=e2/hand have energy gaps ranging from 3 to 20 meV, implying QAH effect at higher temperatures. An effective model Hamiltonian is introduced to understand the topological phase of the heterostructures.
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Affiliation(s)
- Ping Li
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Yuwei You
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Kai Huang
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Weidong Luo
- Key Laboratory of Artificial Structures and Quantum Control, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
- Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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58
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Mende F, Noky J, Guin SN, Fecher GH, Manna K, Adler P, Schnelle W, Sun Y, Fu C, Felser C. Large Anomalous Hall and Nernst Effects in High Curie-Temperature Iron-Based Heusler Compounds. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100782. [PMID: 34240573 PMCID: PMC8425906 DOI: 10.1002/advs.202100782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/29/2021] [Indexed: 05/22/2023]
Abstract
The interplay between topology and magnetism has recently sparked the frontier studies of magnetic topological materials that exhibit intriguing anomalous Hall and Nernst effects owning to the large intrinsic Berry curvature (BC). To better understand the anomalous quantum transport properties of these materials and their implications for future applications such as electronic and thermoelectric devices, it is crucial to discover more novel material platforms for performing anomalous transverse transport studies. Here, it is experimentally demonstrated that low-cost Fe-based Heusler compounds exhibit large anomalous Hall and Nernst effects. An anomalous Hall conductivity of 250-750 S cm-1 and Nernst thermopower of above 2 µV K-1 are observed near room temperature. The positive effect of anti-site disorder on the anomalous Hall transport is revealed. Considering the very high Curie temperature (nearly 1000 K), larger Nernst thermopowers at high temperatures are expected owing to the existing magnetic order and the intrinsic BC. This work provides a background for developing low-cost Fe-based Heusler compounds as a new material platform for anomalous transport studies and applications, in particular, near and above room temperature.
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Affiliation(s)
- Felix Mende
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Jonathan Noky
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Satya N. Guin
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Gerhard H. Fecher
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
- Department of PhysicsIndian Institute of Technology DelhiHauz KhasNew Delhi110016India
| | - Peter Adler
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Walter Schnelle
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Yan Sun
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
| | - Chenguang Fu
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
- State Key Laboratory of Silicon Materials, and School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of SolidsNöthnitzer Str. 40Dresden01187Germany
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59
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Xia B, Gao D, Xue D. Ferromagnetism of two-dimensional transition metal chalcogenides: both theoretical and experimental investigations. NANOSCALE 2021; 13:12772-12787. [PMID: 34477766 DOI: 10.1039/d1nr02967c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In recent years, with the fast development of integrated circuit electronic devices and technologies, it has become urgent to improve the density of data storage and lower the energy losses of devices. Under these circumstances, two-dimensional (2D) materials, which have a smaller size and lower energy loss compared with bulk materials, are becoming ideal candidates for future spintronic devices. Among them, 2D transition metal chalcogenides (TMCs), which have excellent electronic and optical properties, have attracted great attention from researchers. However, most of them are intrinsically non-magnetic, which severely hinders their further applications in spintronics. Therefore, introducing intrinsic room-temperature ferromagnetism into 2D TMC materials has become an important issue in spintronics. In this work, we review the introduction of intrinsic ferromagnetism into typical 2D TMCs using various strategies, such as defect engineering, doping with transition metal elements, and phase transfer. Additionally, we found that their ferromagnetism could be adjusted via changing the experimental conditions, such as the nucleation temperature, ion irradiation dose, doping amount, and phase ratio. Finally, we provide some insight into prospective solutions for introducing ferromagnetism into 2D TMCs, hoping to shed some light on future spintronics development.
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Affiliation(s)
- Baorui Xia
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, 730000, Lanzhou, China.
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60
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Liu C, Wang Y, Yang M, Mao J, Li H, Li Y, Li J, Zhu H, Wang J, Li L, Wu Y, Xu Y, Zhang J, Wang Y. Magnetic-field-induced robust zero Hall plateau state in MnBi 2Te 4 Chern insulator. Nat Commun 2021; 12:4647. [PMID: 34330926 PMCID: PMC8324822 DOI: 10.1038/s41467-021-25002-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
The intrinsic antiferromagnetic topological insulator MnBi2Te4 provides an ideal platform for exploring exotic topological quantum phenomena. Recently, the Chern insulator and axion insulator phases have been realized in few-layer MnBi2Te4 devices at low magnetic field regime. However, the fate of MnBi2Te4 in high magnetic field has never been explored in experiment. In this work, we report transport studies of exfoliated MnBi2Te4 flakes in pulsed magnetic fields up to 61.5 T. In the high-field limit, the Chern insulator phase with Chern number C = -1 evolves into a robust zero Hall resistance plateau state. Nonlocal transport measurements and theoretical calculations demonstrate that the charge transport in the zero Hall plateau state is conducted by two counter-propagating edge states that arise from the combined effects of Landau levels and large Zeeman effect in strong magnetic fields. Our result demonstrates the intricate interplay among intrinsic magnetic order, external magnetic field, and nontrivial band topology in MnBi2Te4.
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Affiliation(s)
- Chang Liu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Yongchao Wang
- Beijing Innovation Center for Future Chips, Tsinghua University, Beijing, China
| | - Ming Yang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Jiahao Mao
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Hao Li
- School of Materials Science and Engineering, Tsinghua University, Beijing, China
- Tsinghua-Foxconn Nanotechnology Research Center, Department of Physics, Tsinghua University, Beijing, China
| | - Yaoxin Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Jiaheng Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Haipeng Zhu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Junfeng Wang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Liang Li
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Wu
- Tsinghua-Foxconn Nanotechnology Research Center, Department of Physics, Tsinghua University, Beijing, China
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Yong Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
- RIKEN Center for Emergent Matter Science, Wako, Saitama, Japan.
- Frontier Science Center for Quantum Information, Beijing, China.
| | - Jinsong Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
- Frontier Science Center for Quantum Information, Beijing, China.
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
- Frontier Science Center for Quantum Information, Beijing, China.
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61
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Zhong H, Bao C, Wang H, Li J, Yin Z, Xu Y, Duan W, Xia TL, Zhou S. Light-Tunable Surface State and Hybridization Gap in Magnetic Topological Insulator MnBi 8Te 13. NANO LETTERS 2021; 21:6080-6086. [PMID: 34242038 DOI: 10.1021/acs.nanolett.1c01448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
MnBi8Te13 is an intrinsic ferromagnetic (FM) topological insulator with different complex surface terminations. Resolving the electronic structures of different termination surfaces and manipulation of the electronic state are important. Here, by using micrometer spot time- and angle-resolved photoemission spectroscopy (μ-TrARPES), we resolve the electronic structures and reveal the ultrafast dynamics upon photoexcitation. Photoinduced filling of the surface state hybridization gap is observed for the Bi2Te3 quintuple layer directly above MnBi2Te4 accompanied by a nontrivial shift of the surface state, suggesting light-tunable interlayer interaction. Relaxation of photoexcited electrons and holes is observed within 1-2 ps. Our work reveals photoexcitation as a potential control knob for tailoring the interlayer interaction and surface state of MnBi8Te13.
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Affiliation(s)
- Haoyuan Zhong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
| | - Changhua Bao
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
| | - Huan Wang
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, P. R. China
| | - Jiaheng Li
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
| | - Zichen Yin
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
| | - Yong Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing 100084, P. R. China
| | - Wenhui Duan
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing 100084, P. R. China
| | - Tian-Long Xia
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, P. R. China
| | - Shuyun Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing 100084, P. R. China
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62
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Choe J, Lujan D, Rodriguez-Vega M, Ye Z, Leonardo A, Quan J, Nunley TN, Chang LJ, Lee SF, Yan J, Fiete GA, He R, Li X. Electron-Phonon and Spin-Lattice Coupling in Atomically Thin Layers of MnBi 2Te 4. NANO LETTERS 2021; 21:6139-6145. [PMID: 34252281 DOI: 10.1021/acs.nanolett.1c01719] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
MnBi2Te4 represents a new class of magnetic topological insulators in which novel quantum phases emerge at temperatures higher than those found in magnetically doped thin films. Here, we investigate how couplings between electron, spin, and lattice are manifested in the phonon spectra of few-septuple-layer thick MnBi2Te4. After categorizing phonon modes by their symmetries, we study the systematic changes in frequency, line width, and line shape of a spectrally isolated A1g mode. The electron-phonon coupling increases in thinner flakes as manifested in a broader phonon line width, which is likely due to changes of the electron density of states. In 4- and 5-septuple thick samples, the onset of magnetic order below the Néel temperature is concurrent with a transition to an insulating state. We observe signatures of a reduced electron-phonon scattering across this transition as reflected in the reduced Fano parameter. Finally, spin-lattice coupling is measured and modeled from temperature-dependent phonon frequency.
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Affiliation(s)
- Jeongheon Choe
- Department of Physics, Center of Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712 United States
- Center for Dynamics and Control of Materials, The University of Texas at Austin, Austin, Texas 78712, United States
| | - David Lujan
- Department of Physics, Center of Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712 United States
- Center for Dynamics and Control of Materials, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Martin Rodriguez-Vega
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Zhipeng Ye
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Aritz Leonardo
- Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastian, Spain
- Department of Physics, University of the Basque Country UPV/EHU, 48940 Leioa, Spain
| | - Jiamin Quan
- Department of Physics, Center of Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712 United States
| | - T Nathan Nunley
- Department of Physics, Center of Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712 United States
| | - Liang-Juan Chang
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712 United States
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Shang-Fan Lee
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Jiaqiang Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gregory A Fiete
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Rui He
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Xiaoqin Li
- Department of Physics, Center of Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712 United States
- Center for Dynamics and Control of Materials, The University of Texas at Austin, Austin, Texas 78712, United States
- Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, United States
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63
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Gao A, Liu YF, Hu C, Qiu JX, Tzschaschel C, Ghosh B, Ho SC, Bérubé D, Chen R, Sun H, Zhang Z, Zhang XY, Wang YX, Wang N, Huang Z, Felser C, Agarwal A, Ding T, Tien HJ, Akey A, Gardener J, Singh B, Watanabe K, Taniguchi T, Burch KS, Bell DC, Zhou BB, Gao W, Lu HZ, Bansil A, Lin H, Chang TR, Fu L, Ma Q, Ni N, Xu SY. Layer Hall effect in a 2D topological axion antiferromagnet. Nature 2021; 595:521-525. [PMID: 34290425 DOI: 10.1038/s41586-021-03679-w] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/27/2021] [Indexed: 11/10/2022]
Abstract
Whereas ferromagnets have been known and used for millennia, antiferromagnets were only discovered in the 1930s1. At large scale, because of the absence of global magnetization, antiferromagnets may seem to behave like any non-magnetic material. At the microscopic level, however, the opposite alignment of spins forms a rich internal structure. In topological antiferromagnets, this internal structure leads to the possibility that the property known as the Berry phase can acquire distinct spatial textures2,3. Here we study this possibility in an antiferromagnetic axion insulator-even-layered, two-dimensional MnBi2Te4-in which spatial degrees of freedom correspond to different layers. We observe a type of Hall effect-the layer Hall effect-in which electrons from the top and bottom layers spontaneously deflect in opposite directions. Specifically, under zero electric field, even-layered MnBi2Te4 shows no anomalous Hall effect. However, applying an electric field leads to the emergence of a large, layer-polarized anomalous Hall effect of about 0.5e2/h (where e is the electron charge and h is Planck's constant). This layer Hall effect uncovers an unusual layer-locked Berry curvature, which serves to characterize the axion insulator state. Moreover, we find that the layer-locked Berry curvature can be manipulated by the axion field formed from the dot product of the electric and magnetic field vectors. Our results offer new pathways to detect and manipulate the internal spatial structure of fully compensated topological antiferromagnets4-9. The layer-locked Berry curvature represents a first step towards spatial engineering of the Berry phase through effects such as layer-specific moiré potential.
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Affiliation(s)
- Anyuan Gao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Yu-Fei Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jian-Xiang Qiu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Christian Tzschaschel
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Barun Ghosh
- Department of Physics, Indian Institute of Technology, Kanpur, India.,Department of Physics, Northeastern University, Boston, MA, USA
| | - Sheng-Chin Ho
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Damien Bérubé
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Rui Chen
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Haipeng Sun
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xin-Yue Zhang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yu-Xuan Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Naizhou Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zumeng Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Amit Agarwal
- Department of Physics, Indian Institute of Technology, Kanpur, India
| | - Thomas Ding
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Hung-Ju Tien
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
| | - Austin Akey
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Jules Gardener
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA
| | - Bahadur Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenneth S Burch
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - David C Bell
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, USA.,Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Brian B Zhou
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Hai-Zhou Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Arun Bansil
- Department of Physics, Northeastern University, Boston, MA, USA
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan.,Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan.,Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Su-Yang Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
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64
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Shao J, Liu Y, Zeng M, Li J, Wu X, Ma XM, Jin F, Lu R, Sun Y, Gu M, Wang K, Wu W, Wu L, Liu C, Liu Q, Zhao Y. Pressure-Tuned Intralayer Exchange in Superlattice-Like MnBi 2Te 4/(Bi 2Te 3) n Topological Insulators. NANO LETTERS 2021; 21:5874-5880. [PMID: 34197120 DOI: 10.1021/acs.nanolett.1c01874] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The magnetic structures of MnBi2Te4(Bi2Te3)n can be manipulated by tuning the interlayer coupling via the number of Bi2Te3 spacer layers n, while the intralayer ferromagnetic (FM) exchange coupling is considered too robust to control. By applying hydrostatic pressure up to 3.5 GPa, we discover opposite responses of magnetic properties for n = 1 and 2. MnBi4Te7 stays at A-type antiferromagnetic (AFM) phase with a decreasing Néel temperature and an increasing saturation field. In sharp contrast, MnBi6Te10 experiences a phase transition from A-type AFM to a quasi-two-dimensional FM state with a suppressed saturation field under pressure. First-principles calculations reveal the essential role of intralayer exchange coupling from lattice compression in determining these magnetic properties. Such magnetic phase transition is also observed in 20% Sb-doped MnBi6Te10 because of the in-plane lattice compression.
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Affiliation(s)
- Jifeng Shao
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuntian Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Meng Zeng
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jingyuan Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuefeng Wu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiao-Ming Ma
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Feng Jin
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Ruie Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yichen Sun
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mingqiang Gu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kedong Wang
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenbin Wu
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Liusuo Wu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qihang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yue Zhao
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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65
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You JY, Gu B, Su G. P-orbital magnetic topological states on square lattice. Natl Sci Rev 2021; 9:nwab114. [PMID: 35481154 PMCID: PMC9037132 DOI: 10.1093/nsr/nwab114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/13/2020] [Accepted: 06/10/2021] [Indexed: 11/13/2022] Open
Abstract
Honeycomb or triangular lattices were extensively studied and thought to be proper platforms for realizing the quantum anomalous Hall effect (QAHE), where magnetism is usually caused by d orbitals of transition metals. Here we propose that a square lattice can host three magnetic topological states, including the fully spin-polarized nodal loop semimetal, QAHE and the topologically trivial ferromagnetic semiconductor, in terms of the symmetry and k · p model analyses that are material independent. A phase diagram is presented. We further show that the above three magnetic topological states can indeed be implemented in the two-dimensional (2D) materials ScLiCl5, LiScZ5 (Z=Cl, Br) and ScLiBr5, respectively. The ferromagnetism in these 2D materials is microscopically revealed from p electrons of halogen atoms. This present study opens a door to explore the exotic topological states as well as quantum magnetism from p-orbital electrons by means of the material-independent approach.
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Affiliation(s)
- Jing-Yang You
- Kavli Institute for Theoretical Sciences, and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Department of Physics, Faculty of Science, National University of Singapore, 117551, Singapore
| | - Bo Gu
- Kavli Institute for Theoretical Sciences, and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Physical Science Laboratory, Huairou National Comprehensive Science Center, Beijing 101400, China
| | - Gang Su
- Kavli Institute for Theoretical Sciences, and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Physical Science Laboratory, Huairou National Comprehensive Science Center, Beijing 101400, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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66
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Gu M, Li J, Sun H, Zhao Y, Liu C, Liu J, Lu H, Liu Q. Spectral signatures of the surface anomalous Hall effect in magnetic axion insulators. Nat Commun 2021; 12:3524. [PMID: 34112796 PMCID: PMC8192549 DOI: 10.1038/s41467-021-23844-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 05/19/2021] [Indexed: 12/02/2022] Open
Abstract
The topological surface states of magnetic topological systems, such as Weyl semimetals and axion insulators, are associated with unconventional transport properties such as nonzero or half-quantized surface anomalous Hall effect. Here we study the surface anomalous Hall effect and its spectral signatures in different magnetic topological phases using both model Hamiltonian and first-principles calculations. We demonstrate that by tailoring the magnetization and interlayer electron hopping, a rich three-dimensional topological phase diagram can be established, including three types of topologically distinct insulating phases bridged by Weyl semimetals, and can be directly mapped to realistic materials such as MnBi2Te4/(Bi2Te3)n systems. Among them, we find that the surface anomalous Hall conductivity in the axion-insulator phase is a well-localized quantity either saturated at or oscillating around e2/2h, depending on the magnetic homogeneity. We also discuss the resultant chiral hinge modes embedded inside the side surface bands as the potential experimental signatures for transport measurements. Our study is a significant step forward towards the direct realization of the long-sought axion insulators in realistic material systems.
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Affiliation(s)
- Mingqiang Gu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Jiayu Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Hongyi Sun
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Yufei Zhao
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Chang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Jianpeng Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, Shanghai, China.
| | - Haizhou Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Qihang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, China.
- Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen, China.
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China.
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67
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Wang P, Ge J, Li J, Liu Y, Xu Y, Wang J. Intrinsic magnetic topological insulators. Innovation (N Y) 2021; 2:100098. [PMID: 34557750 PMCID: PMC8454723 DOI: 10.1016/j.xinn.2021.100098] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/16/2021] [Indexed: 12/02/2022] Open
Abstract
Introducing magnetism into topological insulators breaks time-reversal symmetry, and the magnetic exchange interaction can open a gap in the otherwise gapless topological surface states. This allows various novel topological quantum states to be generated, including the quantum anomalous Hall effect (QAHE) and axion insulator states. Magnetic doping and magnetic proximity are viewed as being useful means of exploring the interaction between topology and magnetism. However, the inhomogeneity of magnetic doping leads to complicated magnetic ordering and small exchange gaps, and consequently the observed QAHE appears only at ultralow temperatures. Therefore, intrinsic magnetic topological insulators are highly desired for increasing the QAHE working temperature and for investigating topological quantum phenomena further. The realization and characterization of such systems are essential for both fundamental physics and potential technical revolutions. This review summarizes recent research progress in intrinsic magnetic topological insulators, focusing mainly on the antiferromagnetic topological insulator MnBi2Te4 and its family of materials.
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Affiliation(s)
- Pinyuan Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Jun Ge
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Jiaheng Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Yanzhao Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Yong Xu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Jian Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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68
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Eremeev SV, Rusinov IP, Koroteev YM, Vyazovskaya AY, Hoffmann M, Echenique PM, Ernst A, Otrokov MM, Chulkov EV. Topological Magnetic Materials of the (MnSb 2Te 4)·(Sb 2Te 3) n van der Waals Compounds Family. J Phys Chem Lett 2021; 12:4268-4277. [PMID: 33908787 DOI: 10.1021/acs.jpclett.1c00875] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Using density functional theory, we propose the (MnSb2Te4)·(Sb2Te3)n family of stoichiometric van der Waals compounds that harbor multiple topologically nontrivial magnetic phases. In the ground state, the first three members of the family (n = 0, 1, 2) are 3D antiferromagnetic topological insulators, while for n ≥ 3 a special phase is formed, in which a nontrivial topological order coexists with a partial magnetic disorder in the system of the decoupled 2D ferromagnets, whose magnetizations point randomly along the third direction. Furthermore, due to a weak interlayer exchange coupling, these materials can be field-driven into the FM Weyl semimetal (n = 0) or FM axion insulator states (n ≥ 1). Finally, in two dimensions, we reveal these systems to show intrinsic quantum anomalous Hall and AFM axion insulator states, as well as quantum Hall state, achieved under external magnetic field. Our results demonstrate that MnSb2Te4 is not topologically trivial as was previously believed that opens possibilities of realization of a wealth of topologically nontrivial states in the (MnSb2Te4)·(Sb2Te3)n family.
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Affiliation(s)
- S V Eremeev
- Institute of Strength Physics and Materials Science, Russian Academy of Sciences, 634021 Tomsk, Russia
- Tomsk State University, 634050 Tomsk, Russia
| | - I P Rusinov
- Tomsk State University, 634050 Tomsk, Russia
- Saint Petersburg State University, 198504 Saint Petersburg, Russia
| | - Yu M Koroteev
- Institute of Strength Physics and Materials Science, Russian Academy of Sciences, 634021 Tomsk, Russia
| | - A Yu Vyazovskaya
- Tomsk State University, 634050 Tomsk, Russia
- Saint Petersburg State University, 198504 Saint Petersburg, Russia
| | - M Hoffmann
- Institut für Theoretische Physik, Johannes Kepler Universität, A 4040 Linz, Austria
| | - P M Echenique
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia-San Sebastián, Basque Country, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
| | - A Ernst
- Institut für Theoretische Physik, Johannes Kepler Universität, A 4040 Linz, Austria
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - M M Otrokov
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - E V Chulkov
- Saint Petersburg State University, 198504 Saint Petersburg, Russia
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia-San Sebastián, Basque Country, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
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69
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Li H, Jiang H, Chen CZ, Xie XC. Critical Behavior and Universal Signature of an Axion Insulator State. PHYSICAL REVIEW LETTERS 2021; 126:156601. [PMID: 33929241 DOI: 10.1103/physrevlett.126.156601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Recently, the search for an axion insulator state in the ferromagnetic-3D topological insulator (TI) heterostructure and MnBi_{2}Te_{4} has attracted intense interest. However, its detection remains difficult in experiments. We systematically investigate the disorder-induced phase transition of the axion insulator state in a 3D TI with antiparallel magnetization alignment surfaces. It is found that there exists a 2D disorder-induced phase transition on the surfaces of the 3D TI which shares the same universality class with the quantum Hall plateau to plateau transition. Then, we provide a phenomenological theory which maps the random mass Dirac Hamiltonian of the axion insulator state into the Chalker-Coddington network model. Therefore, we propose probing the axion insulator state by investigating the universal signature of such a phase transition in the ferromagnetic-3D TI heterostructure and MnBi_{2}Te_{4}. Our findings not only show a global phase diagram of the axion insulator state, but also stimulate further experiments to probe it.
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Affiliation(s)
- Hailong Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Hua Jiang
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
- Institute for Advanced Study, Soochow University, Suzhou 215006, China
| | - Chui-Zhen Chen
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
- Institute for Advanced Study, Soochow University, Suzhou 215006, China
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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70
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Ovchinnikov D, Huang X, Lin Z, Fei Z, Cai J, Song T, He M, Jiang Q, Wang C, Li H, Wang Y, Wu Y, Xiao D, Chu JH, Yan J, Chang CZ, Cui YT, Xu X. Intertwined Topological and Magnetic Orders in Atomically Thin Chern Insulator MnBi 2Te 4. NANO LETTERS 2021; 21:2544-2550. [PMID: 33710884 DOI: 10.1021/acs.nanolett.0c05117] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
MnBi2Te4, a van der Waals magnet, is an emergent platform for exploring Chern insulator physics. Its layered antiferromagnetic order was predicted to enable even-odd layer number dependent topological states. Furthermore, it becomes a Chern insulator when all spins are aligned by an applied magnetic field. However, the evolution of the bulk electronic structure as the magnetic state is continuously tuned and its dependence on layer number remains unexplored. Here, employing multimodal probes, we establish one-to-one correspondence between bulk electronic structure, magnetic state, topological order, and layer thickness in atomically thin MnBi2Te4 devices. As the magnetic state is tuned through the canted magnetic phase, we observe a band crossing, i.e., the closing and reopening of the bulk band gap, corresponding to the concurrent topological phase transition in both even- and odd-layer-number devices. Our findings shed new light on the interplay between band topology and magnetic order in this newly discovered topological magnet.
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Affiliation(s)
- Dmitry Ovchinnikov
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Xiong Huang
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
- Department of Materials Science and Engineering, University of California, Riverside, California 92521, United States
| | - Zhong Lin
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Zaiyao Fei
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Jiaqi Cai
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Tiancheng Song
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Minhao He
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Qianni Jiang
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Chong Wang
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Hao Li
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Yayu Wang
- Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yang Wu
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Jiaqiang Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yong-Tao Cui
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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71
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Zhang S, Xu R, Luo N, Zou X. Two-dimensional magnetic materials: structures, properties and external controls. NANOSCALE 2021; 13:1398-1424. [PMID: 33416064 DOI: 10.1039/d0nr06813f] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Since the discovery of intrinsic ferromagnetism in atomically thin Cr2Gr2Te6 and CrI3 in 2017, research on two-dimensional (2D) magnetic materials has become a highlighted topic. Based on 2D magnetic materials and their heterostructures, exotic physical phenomena at the atomically thin limit have been discovered, such as the quantum anomalous Hall effect, magneto-electric multiferroics, and magnon valleytronics. Furthermore, magnetism in these ultrathin magnets can be effectively controlled by external perturbations, such as electric field, strain, doping, chemical functionalization, and stacking engineering. These attributes make 2D magnets ideal platforms for fundamental research and promising candidates for various spintronic applications. This review aims at providing an overview of the structures, properties, and external controls of 2D magnets, as well as the challenges and potential opportunities in this field.
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Affiliation(s)
- Shuqing Zhang
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) & Tsinghua Shenzhen International Graduate School (TSIGS), Tsinghua University, Shenzhen 518055, China.
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72
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Li YH, Cheng R. Spin Fluctuations in Quantized Transport of Magnetic Topological Insulators. PHYSICAL REVIEW LETTERS 2021; 126:026601. [PMID: 33512203 DOI: 10.1103/physrevlett.126.026601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
In magnetic topological insulators, quantized electronic transport is intertwined with spontaneous magnetic ordering, as magnetization controls band gaps, hence band topology, through the exchange interaction. We show that considering the exchange gaps at the mean-field level is inadequate to predict phase transitions between electronic states of distinct topology. Thermal spin fluctuations disturbing the magnetization can act as frozen disorders that strongly scatter electrons, reducing the onset temperature of quantized transport appreciably even in the absence of structural impurities. This effect, which has hitherto been overlooked, provides an alternative explanation of recent experiments on magnetic topological insulators.
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Affiliation(s)
- Yu-Hang Li
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
- Department of Physics, University of California, Riverside, California 92521, USA
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73
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Liu G, Chen XQ, Liu B, Ren W, Cheng HM. Six-membered-ring inorganic materials: definition and prospects. Natl Sci Rev 2021; 8:nwaa248. [PMID: 34691562 PMCID: PMC8294346 DOI: 10.1093/nsr/nwaa248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/17/2020] [Accepted: 08/06/2020] [Indexed: 11/17/2022] Open
Abstract
The six-membered ring (SMR) is a common structure unit for numerous material systems. These materials include, but are not limited to, the typical two-dimensional materials such as graphene, h-BN, and transition metal dichalcogenides, as well as three-dimensional materials such as beryllium, magnesium, MgB2 and Bi2Se3. Although many of these materials have already become 'stars' in materials science and condensed-matter physics, little attention has been paid to the roles of the SMR unit across a wide range of compositions and structures. In this article, we systematically analyze these materials with respect to their very basic SMR structural unit, which has been found to play a deterministic role in the occurrence of many intriguing properties and phenomena, such as Dirac electronic and phononic spectra, superconductivity and topology. As a result, we have defined this group of materials as SMR inorganic materials, opening up a new perspective on materials research and development. With their unique properties, SMR materials deserve wide attention and in-depth investigation from materials design, new physical discoveries to target-wizard applications. It is expected that SMR materials will find niche applications in next-generation information technology, renewable energy, space, etc.
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Affiliation(s)
- Gang Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Xing-Qiu Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Bilu Liu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Hui-Ming Cheng
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
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Xu L, Mao Y, Wang H, Li J, Chen Y, Xia Y, Li Y, Pei D, Zhang J, Zheng H, Huang K, Zhang C, Cui S, Liang A, Xia W, Su H, Jung S, Cacho C, Wang M, Li G, Xu Y, Guo Y, Yang L, Liu Z, Chen Y, Jiang M. Persistent surface states with diminishing gap in MnBi 2Te 4/Bi 2Te 3 superlattice antiferromagnetic topological insulator. Sci Bull (Beijing) 2020; 65:2086-2093. [PMID: 36732961 DOI: 10.1016/j.scib.2020.07.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 05/02/2020] [Accepted: 07/17/2020] [Indexed: 02/04/2023]
Abstract
Magnetic topological quantum materials (TQMs) provide a fertile ground for the emergence of fascinating topological magneto-electric effects. Recently, the discovery of intrinsic antiferromagnetic (AFM) topological insulator MnBi2Te4 that could realize quantized anomalous Hall effect and axion insulator phase ignited intensive study on this family of TQM compounds. Here, we investigated the AFM compound MnBi4Te7 where Bi2Te3 and MnBi2Te4 layers alternate to form a superlattice. Using spatial- and angle-resolved photoemission spectroscopy, we identified ubiquitous (albeit termination dependent) topological electronic structures from both Bi2Te3 and MnBi2Te4 terminations. Unexpectedly, while the bulk bands show strong temperature dependence correlated with the AFM transition, the topological surface states with a diminishing gap show negligible temperature dependence across the AFM transition. Together with the results of its sister compound MnBi2Te4, we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.
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Affiliation(s)
- Lixuan Xu
- Center for Excellence in Superconducting Electronics, State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanhao Mao
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Hongyuan Wang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiaheng Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yujie Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yunyouyou Xia
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiwei Li
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK
| | - Ding Pei
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK
| | - Jing Zhang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Huijun Zheng
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Kui Huang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Chaofan Zhang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Shengtao Cui
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Aiji Liang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Su
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Sungwon Jung
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - Cephise Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, UK
| | - Meixiao Wang
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Gang Li
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Yong Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Frontier Science Center for Quantum Information, Beijing 100084, China; RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Frontier Science Center for Quantum Information, Beijing 100084, China.
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China.
| | - Yulin Chen
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China; State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China; Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK.
| | - Mianheng Jiang
- Center for Excellence in Superconducting Electronics, State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
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75
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Tuning the Chern number in quantum anomalous Hall insulators. Nature 2020; 588:419-423. [PMID: 33328665 DOI: 10.1038/s41586-020-3020-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 10/02/2020] [Indexed: 11/08/2022]
Abstract
A quantum anomalous Hall (QAH) state is a two-dimensional topological insulating state that has a quantized Hall resistance of h/(Ce2) and vanishing longitudinal resistance under zero magnetic field (where h is the Planck constant, e is the elementary charge, and the Chern number C is an integer)1,2. The QAH effect has been realized in magnetic topological insulators3-9 and magic-angle twisted bilayer graphene10,11. However, the QAH effect at zero magnetic field has so far been realized only for C = 1. Here we realize a well quantized QAH effect with tunable Chern number (up to C = 5) in multilayer structures consisting of alternating magnetic and undoped topological insulator layers, fabricated using molecular beam epitaxy. The Chern number of these QAH insulators is determined by the number of undoped topological insulator layers in the multilayer structure. Moreover, we demonstrate that the Chern number of a given multilayer structure can be tuned by varying either the magnetic doping concentration in the magnetic topological insulator layers or the thickness of the interior magnetic topological insulator layer. We develop a theoretical model to explain our experimental observations and establish phase diagrams for QAH insulators with high, tunable Chern number. The realization of such insulators facilitates the application of dissipationless chiral edge currents in energy-efficient electronic devices, and opens up opportunities for developing multi-channel quantum computing and higher-capacity chiral circuit interconnects.
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76
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Huang B, McGuire MA, May AF, Xiao D, Jarillo-Herrero P, Xu X. Emergent phenomena and proximity effects in two-dimensional magnets and heterostructures. NATURE MATERIALS 2020; 19:1276-1289. [PMID: 32948831 DOI: 10.1038/s41563-020-0791-8] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 07/30/2020] [Indexed: 05/24/2023]
Abstract
Ultrathin van der Waals materials and their heterostructures offer a simple, yet powerful platform for discovering emergent phenomena and implementing device structures in the two-dimensional limit. The past few years has pushed this frontier to include magnetism. These advances have brought forth a new assortment of layered materials that intrinsically possess a wide variety of magnetic properties and are instrumental in integrating exchange and spin-orbit interactions into van der Waals heterostructures. This Review Article summarizes recent progress in exploring the intrinsic magnetism of atomically thin van der Waals materials, manipulation of their magnetism by tuning the interlayer coupling, and device structures for spin- and valleytronic applications.
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Affiliation(s)
- Bevin Huang
- Department of Physics, University of Washington, Seattle, WA, USA.
| | - Michael A McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
| | | | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
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77
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Lei C, Chen S, MacDonald AH. Magnetized topological insulator multilayers. Proc Natl Acad Sci U S A 2020; 117:27224-27230. [PMID: 33077591 PMCID: PMC7959519 DOI: 10.1073/pnas.2014004117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We discuss the magnetic and topological properties of bulk crystals and quasi-two-dimensional (quasi-2D) thin films formed by stacking intrinsic magnetized topological insulator (for example, Mn ([Formula: see text])2X4 with X = Se,Te) septuple layers and topological insulator quintuple layers in arbitrary order. Our analysis makes use of a simplified model that retains only Dirac cone degrees of freedom on both surfaces of each septuple or quintuple layer. We demonstrate the model's applicability and estimate its parameters by comparing with ab initio density-functional theory (DFT) calculations. We then employ the coupled Dirac cone model to provide an explanation for the dependence of thin-film properties, particularly the presence or absence of the quantum anomalous Hall effect, on film thickness, magnetic configuration, and stacking arrangement, and to comment on the design of Weyl superlattices.
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Affiliation(s)
- Chao Lei
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Shu Chen
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
- Department of Physics, Shanghai University, Shanghai 200444, China
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX 78712;
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78
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Hou F, Yao Q, Zhou CS, Ma XM, Han M, Hao YJ, Wu X, Zhang Y, Sun H, Liu C, Zhao Y, Liu Q, Lin J. Te-Vacancy-Induced Surface Collapse and Reconstruction in Antiferromagnetic Topological Insulator MnBi 2Te 4. ACS NANO 2020; 14:11262-11272. [PMID: 32813492 DOI: 10.1021/acsnano.0c03149] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
MnBi2Te4 is an antiferromagnetic topological insulator that has stimulated intense interest due to its exotic quantum phenomena and promising device applications. The surface structure is a determinant factor to understand the magnetic and topological behavior of MnBi2Te4, yet its precise atomic structure remains elusive. Here we discovered a surface collapse and reconstruction of few-layer MnBi2Te4 exfoliated under delicate protection. Instead of the ideal septuple-layer structure in the bulk, the collapsed surface is shown to reconstruct as a Mn-doped Bi2Te3 quintuple layer and a MnxBiyTe double layer with a clear van der Waals gap in between. Combined with first-principles calculations, such surface collapse is attributed to the abundant intrinsic Mn-Bi antisite defects and the tellurium vacancy in the exfoliated surface, which is further supported by in situ annealing and electron irradiation experiments. Our results shed light on the understanding of the intricate surface-bulk correspondence of MnBi2Te4 and provide an insightful perspective on the surface-related quantum measurements in MnBi2Te4 few-layer devices.
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Affiliation(s)
- Fuchen Hou
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qiushi Yao
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Chun-Sheng Zhou
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Xiao-Ming Ma
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Mengjiao Han
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yu-Jie Hao
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Xuefeng Wu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Yu Zhang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Department of Physics, University of Hong Kong, Hong Kong, P. R. China
| | - Hongyi Sun
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
| | - Chang Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Yue Zhao
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Qihang Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, P. R. China
- Guangdong Provincial Key Laboratory for Computational Science and Material Design, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
| | - Junhao Lin
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P. R. China
- Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
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79
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Li H, Liu H, Jiang H, Xie XC. 3D Quantum Hall Effect and a Global Picture of Edge States in Weyl Semimetals. PHYSICAL REVIEW LETTERS 2020; 125:036602. [PMID: 32745387 DOI: 10.1103/physrevlett.125.036602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/08/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
We investigate the 3D quantum Hall effect in Weyl semimetals and elucidate a global picture of the edge states. The edge states hosting 3D quantum Hall effect are combinations of Fermi arcs and chiral Landau bands dispersing along the magnetic field direction. The Hall conductance, σ_{xz}^{H} [see Fig. 4], shows quantized plateaus with the variance of the magnetic field when the Fermi level is at the Weyl node. However, the chiral Landau bands can change the spatial distribution of the edge states, especially under a tilted magnetic field, and the resulting edge states lead to distinctive Hall transport phenomena. A tilted magnetic field contributes an intrinsic value to σ_{xz}^{H} and such an intrinsic value is determined by the tilting angle θ between the magnetic field and the y axis [see Fig. 1(c)]. Particularly, even if the perpendicular magnetic field is fixed, σ_{xz}^{H} will change its sign with an abrupt spatial shift of the edge states when θ exceeds a critical angle θ_{c}. Our work uncovers the novel edge-state nature of the 3D quantum Hall effect in Weyl semimetals.
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Affiliation(s)
- Hailong Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Haiwen Liu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Hua Jiang
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
- Institute for Advanced Study, Soochow University, Suzhou 215006, China
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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Tan A, Labracherie V, Kunchur N, Wolter AUB, Cornejo J, Dufouleur J, Büchner B, Isaeva A, Giraud R. Metamagnetism of Weakly Coupled Antiferromagnetic Topological Insulators. PHYSICAL REVIEW LETTERS 2020; 124:197201. [PMID: 32469595 DOI: 10.1103/physrevlett.124.197201] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/27/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
The magnetic properties of the van der Waals magnetic topological insulators MnBi_{2}Te_{4} and MnBi_{4}Te_{7} are investigated by magnetotransport measurements. We evidence that the relative strength of the interlayer exchange coupling J to the uniaxial anisotropy K controls a transition from an A-type antiferromagnetic order to a ferromagneticlike metamagnetic state. A bilayer Stoner-Wohlfarth model allows us to describe this evolution, as well as the typical angular dependence of specific signatures, such as the spin-flop transition of the uniaxial antiferromagnet and the switching field of the metamagnet.
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Affiliation(s)
- Aoyu Tan
- Université Grenoble Alpes, CNRS, CEA, Spintec, F-38000 Grenoble, France
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
| | - Valentin Labracherie
- Université Grenoble Alpes, CNRS, CEA, Spintec, F-38000 Grenoble, France
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
| | - Narayan Kunchur
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
| | - Anja U B Wolter
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
| | - Joaquin Cornejo
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
| | - Joseph Dufouleur
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
- Center for Transport and Devices, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Bernd Büchner
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
- Institut für Festkörperphysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Anna Isaeva
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
- Institut für Festkörperphysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Romain Giraud
- Université Grenoble Alpes, CNRS, CEA, Spintec, F-38000 Grenoble, France
- Institute for Solid State Physics, Leibniz IFW Dresden, D-01069 Dresden, Germany
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Fu H, Liu CX, Yan B. Exchange bias and quantum anomalous nomalous Hall effect in the MnBi 2Te 4/CrI 3 heterostructure. SCIENCE ADVANCES 2020; 6:eaaz0948. [PMID: 32181356 PMCID: PMC7060064 DOI: 10.1126/sciadv.aaz0948] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/11/2019] [Indexed: 05/31/2023]
Abstract
The layered antiferromagnetic MnBi2Te4 films have been proposed to be an intrinsic quantum anomalous Hall (QAH) insulator with a large gap. It is crucial to open a magnetic gap of surface states. However, recent experiments have observed gapless surface states, indicating the absence of out-of-plane surface magnetism, and thus, the quantized Hall resistance can only be achieved at the magnetic field above 6 T. We propose to induce out-of-plane surface magnetism of MnBi2Te4 films via the magnetic proximity with magnetic insulator CrI3. A strong exchange bias of ∼40 meV originates from the long Cr-eg orbital tails that hybridize strongly with Te p orbitals. By stabilizing surface magnetism, the QAH effect can be realized in the MnBi2Te4/CrI3 heterostructure. Moreover, the high-Chern number QAH state can be achieved by controlling external electric gates. Thus, the MnBi2Te4/CrI3 heterostructure provides a promising platform to realize the electrically tunable zero-field QAH effect.
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Affiliation(s)
- Huixia Fu
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Chao-Xing Liu
- Department of Physics, the Pennsylvania State University, University Park, PA 16802, USA
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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