1
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Yuan W, Yan ZJ, Yi H, Wang Z, Paolini S, Zhao YF, Zhou L, Wang AG, Wang K, Prokscha T, Salman Z, Suter A, Balakrishnan PP, Grutter AJ, Winter LE, Singleton J, Chan MHW, Chang CZ. Coexistence of Superconductivity and Antiferromagnetism in Topological Magnet MnBi 2Te 4 Films. NANO LETTERS 2024. [PMID: 38885199 DOI: 10.1021/acs.nanolett.4c01407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The interface of two materials can harbor unexpected emergent phenomena. One example is interface-induced superconductivity. In this work, we employ molecular beam epitaxy to grow a series of heterostructures formed by stacking together two nonsuperconducting antiferromagnetic materials, an intrinsic antiferromagnetic topological insulator MnBi2Te4 and an antiferromagnetic iron chalcogenide FeTe. Our electrical transport measurements reveal interface-induced superconductivity in these heterostructures. By performing scanning tunneling microscopy and spectroscopy measurements, we observe a proximity-induced superconducting gap on the top surface of the MnBi2Te4 layer, confirming the coexistence of superconductivity and antiferromagnetism in the MnBi2Te4 layer. Our findings will advance the fundamental inquiries into the topological superconducting phase in hybrid devices and provide a promising platform for the exploration of chiral Majorana physics in MnBi2Te4-based heterostructures.
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Affiliation(s)
- Wei Yuan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zi-Jie Yan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hemian Yi
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zihao Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Stephen Paolini
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Lingjie Zhou
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Annie G Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ke Wang
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Thomas Prokscha
- Laboratory for Muon Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Zaher Salman
- Laboratory for Muon Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Andreas Suter
- Laboratory for Muon Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Purnima P Balakrishnan
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Laurel E Winter
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87544, United States
| | - John Singleton
- National High Magnetic Field Laboratory, Los Alamos, New Mexico 87544, United States
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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2
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Li Y, Wang Y, Lian Z, Li H, Gao Z, Xu L, Wang H, Lu R, Li L, Feng Y, Zhu J, Liu L, Wang Y, Fu B, Yang S, Yang L, Wang Y, Xia T, Liu C, Jia S, Wu Y, Zhang J, Wang Y, Liu C. Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBi 2Te 4. Nat Commun 2024; 15:3399. [PMID: 38649376 PMCID: PMC11035656 DOI: 10.1038/s41467-024-47779-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
The van der Waals antiferromagnetic topological insulator MnBi2Te4 represents a promising platform for exploring the layer-dependent magnetism and topological states of matter. Recently observed discrepancies between magnetic and transport properties have aroused controversies concerning the topological nature of MnBi2Te4 in the ground state. In this article, we demonstrate that fabrication can induce mismatched even-odd layer dependent magnetotransport in few-layer MnBi2Te4. We perform a comprehensive study of the magnetotransport properties in 6- and 7-septuple-layer MnBi2Te4, and reveal that both even- and odd-number-layer device can show zero Hall plateau phenomena in zero magnetic field. Importantly, a statistical survey of the optical contrast in more than 200 MnBi2Te4 flakes reveals that the zero Hall plateau in odd-number-layer devices arises from the reduction of the effective thickness during the fabrication, a factor that was rarely noticed in previous studies of 2D materials. Our finding not only provides an explanation to the controversies regarding the discrepancy of the even-odd layer dependent magnetotransport in MnBi2Te4, but also highlights the critical issues concerning the fabrication and characterization of 2D material devices.
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Affiliation(s)
- Yaoxin Li
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
| | - Yongchao Wang
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
| | - Zichen Lian
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
| | - Hao Li
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
- Department of Physics, Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing, 100084, China
| | - Zhiting Gao
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Liangcai Xu
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
| | - Huan Wang
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Rui'e Lu
- School of Mechanical and Electric Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Longfei Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Yang Feng
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Jinjiang Zhu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200433, China
| | - Liangyang Liu
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
| | - Yongqian Wang
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Bohan Fu
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shuai Yang
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Luyi Yang
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
- Frontier Science Center for Quantum Information, Beijing, 100084, China
| | - Yihua Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200433, China
- Shanghai Research Center for Quantum Sciences, Shanghai, 201315, China
| | - Tianlong Xia
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Chang Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yang Wu
- College of Math and Physics, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Jinsong Zhang
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
- Frontier Science Center for Quantum Information, Beijing, 100084, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Yayu Wang
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China
- Frontier Science Center for Quantum Information, Beijing, 100084, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Chang Liu
- Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Renmin University of China, 100872, Beijing, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China.
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3
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Chong SK, Lei C, Cheng Y, Lee SH, Mao Z, MacDonald AH, Wang KL. Exchange-Driven Chern States in High-Mobility Intrinsic Magnetic Topological Insulators. PHYSICAL REVIEW LETTERS 2024; 132:146601. [PMID: 38640375 DOI: 10.1103/physrevlett.132.146601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/25/2024] [Accepted: 03/12/2024] [Indexed: 04/21/2024]
Abstract
The layer-dependent Chern number (C) in MnBi_{2}Te_{4} is characterized by the presence of a Weyl semimetal state in the ferromagnetic coupling. However, the influence of a key factor, namely, the exchange coupling, remains unexplored. This study focuses on characterizing the C=2 state in MnBi_{2}Te_{4}, which is classified as a higher C state resulting from the anomalous n=0 Landau levels (LLs). Our findings demonstrate that the exchange coupling parameter strongly influences the formation of this Chern state, leading to a competition between the C=1 and 2 states. Moreover, the emergence of odd-even LL sequences, resulting from the breaking of LL degeneracy, provides compelling evidence for the strong exchange coupling strength. These findings highlight the significance of the exchange coupling in understanding the behavior of Chern states and LLs in magnetic quantum systems.
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Affiliation(s)
- Su Kong Chong
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, USA
| | - Chao Lei
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, USA
| | - Seng Huat Lee
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Zhiqiang Mao
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, USA
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4
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Chong SK, Cheng Y, Man H, Lee SH, Wang Y, Dai B, Tanabe M, Yang TH, Mao Z, Moler KA, Wang KL. Intrinsic exchange biased anomalous Hall effect in an uncompensated antiferromagnet MnBi 2Te 4. Nat Commun 2024; 15:2881. [PMID: 38570519 PMCID: PMC10991375 DOI: 10.1038/s41467-024-46689-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 03/06/2024] [Indexed: 04/05/2024] Open
Abstract
Achieving spin-pinning at the interface of hetero-bilayer ferromagnet/antiferromagnet structures in conventional exchange bias systems can be challenging due to difficulties in interface control and the weakening of spin-pinning caused by poor interface quality. In this work, we propose an alternative approach to stabilize the exchange interaction at the interface of an uncompensated antiferromagnet by utilizing a gradient of interlayer exchange coupling. We demonstrate this exchange interaction through a designed field training protocol in the odd-layer topological antiferromagnet MnBi2Te4. Our results reveal a remarkable field-trained exchange bias of up to ~ 400 mT, which exhibits high repeatability and can be easily reset by a large training field. Notably, this field-trained exchange bias effect persists even with zero-field initialization, presenting a stark contrast to the traditional field-cooled exchange bias. The highly tunable exchange bias observed in this single antiferromagnet compound, without the need for an additional magnetic layer, provides valuable insight into the exchange interaction mechanism. These findings pave the way for the systematic design of topological antiferromagnetic spintronics.
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Affiliation(s)
- Su Kong Chong
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA.
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Huiyuan Man
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA
| | - Seng Huat Lee
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yu Wang
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Bingqian Dai
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Masaki Tanabe
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Ting-Hsun Yang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Zhiqiang Mao
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Kathryn A Moler
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Physics and Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, 90095, USA.
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5
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Tang J, Cheng R. Lossless Spin-Orbit Torque in Antiferromagnetic Topological Insulator MnBi_{2}Te_{4}. PHYSICAL REVIEW LETTERS 2024; 132:136701. [PMID: 38613287 DOI: 10.1103/physrevlett.132.136701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 08/22/2023] [Accepted: 02/23/2024] [Indexed: 04/14/2024]
Abstract
We formulate and quantify the spin-orbit torque (SOT) in intrinsic antiferromagnetic topological insulator MnBi_{2}Te_{4} of a few septuple-layer thick in charge-neutral condition, which exhibits pronounced layer-resolved characteristics and even-odd contrast. Contrary to traditional current-induced torques, our SOT is not accompanied by Ohm's currents, thus being devoid of Joule heating. We study the SOT-induced magnetic resonances, where in the tri-septuple-layer case we identify a peculiar exchange mode that is blind to microwaves but can be exclusively driven by the predicted SOT. As an inverse effect, the dynamical magnetic moments generate a pure adiabatic current, which occurs concomitantly with the SOT and gives rise to an overall reactance for the MnBi_{2}Te_{4}, enabling a lossless conversion of electric power into magnetic dynamics.
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Affiliation(s)
- Junyu Tang
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Ran Cheng
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
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6
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Zhu K, Cheng Y, Liao M, Chong SK, Zhang D, He K, Wang KL, Chang K, Deng P. Unveiling the Anomalous Hall Response of the Magnetic Structure Changes in the Epitaxial MnBi 2Te 4 Films. NANO LETTERS 2024; 24:2181-2187. [PMID: 38340079 PMCID: PMC10885191 DOI: 10.1021/acs.nanolett.3c04095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Recently discovered as an intrinsic antiferromagnetic topological insulator, MnBi2Te4 has attracted tremendous research interest, as it provides an ideal platform to explore the interplay between topological and magnetic orders. MnBi2Te4 displays distinct exotic topological phases that are inextricably linked to the different magnetic structures of the material. In this study, we conducted electrical transport measurements and systematically investigated the anomalous Hall response of epitaxial MnBi2Te4 films when subjected to an external magnetic field sweep, revealing the different magnetic structures stemming from the interplay of applied fields and the material's intrinsic antiferromagnetic (AFM) ordering. Our results demonstrate that the nonsquare anomalous Hall loop is a consequence of the distinct reversal processes within individual septuple layers. These findings shed light on the intricate magnetic structures in MnBi2Te4 and related materials, offering insights into understanding their transport properties and facilitating the implementation of AFM topological electronics.
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Affiliation(s)
- Kejing Zhu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Menghan Liao
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Su Kong Chong
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Ding Zhang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Ke He
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Kai Chang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Peng Deng
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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7
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Mei R, Zhao YF, Wang C, Ren Y, Xiao D, Chang CZ, Liu CX. Electrically Controlled Anomalous Hall Effect and Orbital Magnetization in Topological Magnet MnBi_{2}Te_{4}. PHYSICAL REVIEW LETTERS 2024; 132:066604. [PMID: 38394580 DOI: 10.1103/physrevlett.132.066604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 12/22/2023] [Indexed: 02/25/2024]
Abstract
We propose an intrinsic mechanism to understand the even-odd effect, namely, opposite signs of anomalous Hall resistance and different shapes of hysteresis loops for even and odd septuple layers (SLs), of MBE-grown MnBi_{2}Te_{4} thin films with electron doping. The nonzero hysteresis loops in the anomalous Hall effect and magnetic circular dichroism for even-SLs MnBi_{2}Te_{4} films originate from two different antiferromagnetic (AFM) configurations with different zeroth Landau level energies of surface states. The complex form of the anomalous Hall hysteresis loop can be understood from two magnetic transitions, a transition between two AFM states followed by a second transition to the ferromagnetic state. Our model also clarifies the relationship and distinction between axion parameter and magnetoelectric coefficient, and shows an even-odd oscillation behavior of magnetoelectric coefficients in MnBi_{2}Te_{4} films.
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Affiliation(s)
- Ruobing Mei
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chong Wang
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Yafei Ren
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Di Xiao
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chao-Xing Liu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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8
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Li S, Liu T, Liu C, Wang Y, Lu HZ, Xie XC. Progress on the antiferromagnetic topological insulator MnBi 2Te 4. Natl Sci Rev 2024; 11:nwac296. [PMID: 38213528 PMCID: PMC10776361 DOI: 10.1093/nsr/nwac296] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 10/18/2022] [Accepted: 11/09/2022] [Indexed: 01/13/2024] Open
Abstract
Topological materials, which feature robust surface and/or edge states, have now been a research focus in condensed matter physics. They represent a new class of materials exhibiting nontrivial topological phases, and provide a platform for exploring exotic transport phenomena, such as the quantum anomalous Hall effect and the quantum spin Hall effect. Recently, magnetic topological materials have attracted considerable interests due to the possibility to study the interplay between topological and magnetic orders. In particular, the quantum anomalous Hall and axion insulator phases can be realized in topological insulators with magnetic order. MnBi2Te4, as the first intrinsic antiferromagnetic topological insulator discovered, allows the examination of existing theoretical predictions; it has been extensively studied, and many new discoveries have been made. Here we review the progress made on MnBi2Te4 from both experimental and theoretical aspects. The bulk crystal and magnetic structures are surveyed first, followed by a review of theoretical calculations and experimental probes on the band structure and surface states, and a discussion of various exotic phases that can be realized in MnBi2Te4. The properties of MnBi2Te4 thin films and the corresponding transport studies are then reviewed, with an emphasis on the edge state transport. Possible future research directions in this field are also discussed.
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Affiliation(s)
- Shuai Li
- Department of Physics, Harbin Institute of Technology, Harbin 150001, China
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen 518045, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Tianyu Liu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen 518045, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Chang Liu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Yayu Wang
- 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
- Hefei National Laboratory, Hefei 230088, China
| | - Hai-Zhou Lu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen 518045, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - X C Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Hefei National Laboratory, Hefei 230088, China
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9
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Bai Y, Li Y, Luan J, Liu R, Song W, Chen Y, Ji PF, Zhang Q, Meng F, Tong B, Li L, Jiang Y, Gao Z, Gu L, Zhang J, Wang Y, Xue QK, He K, Feng Y, Feng X. Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown MnBi 2Te 4 thin films. Natl Sci Rev 2024; 11:nwad189. [PMID: 38213514 PMCID: PMC10776363 DOI: 10.1093/nsr/nwad189] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/29/2023] [Accepted: 05/16/2023] [Indexed: 01/13/2024] Open
Abstract
The intrinsic magnetic topological insulator MnBi2Te4 provides a feasible pathway to the high-temperature quantum anomalous Hall (QAH) effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4 thin flakes, it remains a big challenge to achieve molecular beam epitaxy (MBE)-grown MnBi2Te4 thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4 thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4 and to find a way out of the big difficulty in obtaining MnBi2Te4 samples showing quantized transport properties.
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Affiliation(s)
- Yunhe Bai
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Yuanzhao Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Jianli Luan
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Ruixuan Liu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Wenyu Song
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Yang Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Peng-Fei Ji
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Qinghua Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Fanqi Meng
- School of Materials Science and Engineering, Tsinghua University, Beijing100084, China
| | - Bingbing Tong
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Lin Li
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Yuying Jiang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Zongwei Gao
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Lin Gu
- School of Materials Science and Engineering, Tsinghua University, Beijing100084, China
| | - Jinsong Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Hefei National Laboratory, Hefei230088, China
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Hefei National Laboratory, Hefei230088, China
| | - Qi-Kun Xue
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Southern University of Science and Technology, Shenzhen518055, China
| | - Ke He
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Hefei National Laboratory, Hefei230088, China
| | - Yang Feng
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Xiao Feng
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Hefei National Laboratory, Hefei230088, China
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10
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Xu R, Xu L, Liu Z, Yang L, Chen Y. ARPES investigation of the electronic structure and its evolution in magnetic topological insulator MnBi 2+2nTe 4+3n family. Natl Sci Rev 2024; 11:nwad313. [PMID: 38327664 PMCID: PMC10849349 DOI: 10.1093/nsr/nwad313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 02/09/2024] Open
Abstract
In the past 5 years, there has been significant research interest in the intrinsic magnetic topological insulator family compounds MnBi2+2nTe4+3n (where n = 0, 1, 2 …). In particular, exfoliated thin films of MnBi2Te4 have led to numerous experimental breakthroughs, such as the quantum anomalous Hall effect, axion insulator phase and high-Chern number quantum Hall effect without Landau levels. However, despite extensive efforts, the energy gap of the topological surface states due to exchange magnetic coupling, which is a key feature of the characteristic band structure of the system, remains experimentally elusive. The electronic structure measured by using angle-resolved photoemission (ARPES) shows significant deviation from ab initio prediction and scanning tunneling spectroscopy measurements, making it challenging to understand the transport results based on the electronic structure. This paper reviews the measurements of the band structure of MnBi2+2nTe4+3n magnetic topological insulators using ARPES, focusing on the evolution of their electronic structures with temperature, surface and bulk doping and film thickness. The aim of the review is to construct a unified picture of the electronic structure of MnBi2+2nTe4+3n compounds and explore possible control of their topological properties.
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Affiliation(s)
- Runzhe Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Lixuan Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai 201210, 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
| | - 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
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, 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
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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11
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Hu C, Qian T, Ni N. Recent progress in MnBi 2nTe 3n+1 intrinsic magnetic topological insulators: crystal growth, magnetism and chemical disorder. Natl Sci Rev 2024; 11:nwad282. [PMID: 38213523 PMCID: PMC10776370 DOI: 10.1093/nsr/nwad282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/19/2023] [Accepted: 09/06/2023] [Indexed: 01/13/2024] Open
Abstract
The search for magnetic topological materials has been at the forefront of condensed matter research for their potential to host exotic states such as axion insulators, magnetic Weyl semimetals, Chern insulators, etc. To date, the MnBi2nTe3n+1 family is the only group of materials showcasing van der Waals-layered structures, intrinsic magnetism and non-trivial band topology without trivial bands at the Fermi level. The interplay between magnetism and band topology in this family has led to the proposal of various topological phenomena, including the quantum anomalous Hall effect, quantum spin Hall effect and quantum magnetoelectric effect. Among these, the quantum anomalous Hall effect has been experimentally observed at record-high temperatures, highlighting the unprecedented potential of this family of materials in fundamental science and technological innovation. In this paper, we provide a comprehensive review of the research progress in this intrinsic magnetic topological insulator family, with a focus on single-crystal growth, characterization of chemical disorder, manipulation of magnetism through chemical substitution and external pressure, and important questions that remain to be conclusively answered.
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Affiliation(s)
- Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Tiema Qian
- Department of Physics and Astronomy and California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
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12
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Han X, Yi HT, Oh S, Wu L. Magneto-optical Effects of an Artificially Layered Ferromagnetic Topological Insulator with a TC of 160 K. NANO LETTERS 2024; 24:914-919. [PMID: 38190329 DOI: 10.1021/acs.nanolett.3c04103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Magnetic topological insulators are a fertile platform for studying the interplay between magnetism and topology. The unique electronic band structure can induce exotic transport and optical properties. However, a comprehensive optical study at both near-infrared and terahertz frequencies has been lacking. Here, we report magneto-optical effects from a heterostructure of a Cr-incorporated topological insulator, CBST. By measuring the magneto-optical Kerr effect, we observe a high temperature ferromagnetic transition (160 K) in the CBST film. We also use time-domain terahertz polarimetry to reveal a terahertz Faraday rotation of 1.5 mrad and a terahertz Kerr rotation of 3.6 mrad at 2 K. The calculated terahertz Hall conductance is 0.42 e2/h. Our work shows the optical responses of an artificially layered magnetic topological insulator, paving the way toward a high-temperature quantum anomalous Hall effect via heterostructure engineering.
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Affiliation(s)
- Xingyue Han
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hee Taek Yi
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Seongshik Oh
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Liang Wu
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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13
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Wu J, Feng Y, Ren Y, Zhang Z, Yang Y, Wang X, Su F, Dong H, Lu Y, Zhang X, Deng Y, Xiang B, Chen Z. Pressure-cycling induced transition behaviors of MnBi2Te4. J Chem Phys 2024; 160:034707. [PMID: 38235798 DOI: 10.1063/5.0184624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/25/2023] [Indexed: 01/19/2024] Open
Abstract
MnBi2Te4 can generate a variety of exotic topological quantum states, which are closely related to its special structure. We conduct comprehensive multiple-cycle high-pressure research on MnBi2Te4 by using a diamond anvil cell to study its phase transition behaviors under high pressure. As observed, when the pressure does not exceed 15 GPa, the material undergoes an irreversible metal-semiconductor-metal transition, whereas when the pressure exceeds 17 GPa, the layered structure is damaged and becomes irreversibly amorphous due to the lattice distortion caused by compression, but it is not completely amorphous, which presents some nano-sized grains after decompression. Our investigation vividly reveals the phase transition behaviors of MnBi2Te4 under high pressure cycling and paves the experimental way to find topological phases under high pressure.
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Affiliation(s)
- Jie Wu
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Yan Feng
- Department of Materials Science and Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei 230026, China
| | - Yifeng Ren
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Ziyou Zhang
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Yanping Yang
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Xinyao Wang
- University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Fuhai Su
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Hongliang Dong
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Yang Lu
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
| | - Xiaojun Zhang
- Arrayed Materials (China) Co., Ltd., Shenzhen 518000, China
| | - Yu Deng
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Bin Xiang
- Department of Materials Science and Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei 230026, China
| | - Zhiqiang Chen
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China
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14
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Liu S, Yu JX, Zhang E, Li Z, Sun Q, Zhang Y, Cao L, Li L, Zhao M, Leng P, Cao X, Li A, Zou J, Kou X, Zang J, Xiu F. Gate-tunable Intrinsic Anomalous Hall Effect in Epitaxial MnBi 2Te 4 Films. NANO LETTERS 2024; 24:16-25. [PMID: 38109350 DOI: 10.1021/acs.nanolett.3c02926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The anomalous Hall effect (AHE) is an important transport signature revealing topological properties of magnetic materials and their spin textures. Recently, MnBi2Te4 has been demonstrated to be an intrinsic magnetic topological insulator. However, the origin of its intriguing AHE behaviors remains elusive. Here, we demonstrate the Berry curvature-dominated intrinsic AHE in wafer-scale MnBi2Te4 films. By applying back-gate voltages, we observe an ambipolar conduction and n-p transition in ∼7-layer MnBi2Te4, where a quadratic relation between the AHE resistance and longitudinal resistance suggests its intrinsic AHE nature. In particular, for ∼3-layer MnBi2Te4, the AHE sign can be tuned from pristine negative to positive. First-principles calculations unveil that such an AHE reversal originated from the competing Berry curvature between oppositely polarized spin-minority-dominated surface states and spin-majority-dominated inner bands. Our results shed light on the underlying physical mechanism of the intrinsic AHE and provide new perspectives for the unconventional sign-tunable AHE.
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Affiliation(s)
- Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
| | - Jie-Xiang Yu
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Zihan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
| | - Qiang Sun
- Materials Engineering, The University of Queensland, Brisbane QLD 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane QLD 4072, Australia
| | - Yong Zhang
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Liwei Cao
- Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China
| | - Lun Li
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Minhao Zhao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
| | - Pengliang Leng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
| | - Xiangyu Cao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
| | - Ang Li
- Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China
| | - Jin Zou
- Materials Engineering, The University of Queensland, Brisbane QLD 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane QLD 4072, Australia
| | - Xufeng Kou
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiadong Zang
- Department of Physics and Astronomy, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, 41st Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, Shanghai 200232, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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15
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Andersen MP, Mikheev E, Rosen IT, Tai L, Zhang P, Wang KL, Kastner MA, Goldhaber-Gordon D. Universal Conductance Fluctuations in a MnBi 2Te 4 Thin Film. NANO LETTERS 2023. [PMID: 38029283 DOI: 10.1021/acs.nanolett.3c02932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Quantum coherence of electrons can produce striking behaviors in mesoscopic conductors. Although magnetic order can also strongly affect transport, the combination of coherence and magnetic order has been largely unexplored. Here, we examine quantum coherence-driven universal conductance fluctuations in the antiferromagnetic, canted antiferromagnetic, and ferromagnetic phases of a thin film of the topological material MnBi2Te4. In each magnetic phase, we extract a charge carrier phase coherence length of about 100 nm. The conductance magnetofingerprint is repeatable when sweeping applied magnetic field within one magnetic phase. Surprisingly, in the antiferromagnetic and canted antiferromagnetic phases, but not in the ferromagnetic phase, the magnetofingerprint depends on the direction of the field sweep. To explain our observations, we suggest that conductance fluctuation measurements are sensitive to the motion and nucleation of magnetic domain walls in MnBi2Te4.
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Affiliation(s)
- Molly P Andersen
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Evgeny Mikheev
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Ilan T Rosen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Lixuan Tai
- Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Peng Zhang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Marc A Kastner
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, Stanford University, Stanford, California 94305, United States
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - David Goldhaber-Gordon
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Physics, Stanford University, Stanford, California 94305, United States
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16
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Ahn J, Kang SH, Yoon M, Ganesh P, Krogel JT. Stacking Faults and Topological Properties in MnBi 2Te 4: Reconciling Gapped and Gapless States. J Phys Chem Lett 2023; 14:9052-9059. [PMID: 37782759 DOI: 10.1021/acs.jpclett.3c01939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Despite theoretical predictions of a gapped surface state for the magnetic topological insulator MnBi2Te4 (MBT), there has been a series of experimental evidence pointing toward gapless states. Here, we theoretically explore how stacking faults could influence the topological characteristics of MBT. We envisage a scenario that a stacking fault exists at the surface of MBT, causing the uppermost layer to deviate from the ground state and its interlayer separation to be expanded. This stacking fault with modulated interlayer couplings hosts a nearly gapless state within the topmost layer due to charge redistribution as the outermost layer recedes. Furthermore, we find evidence of spin-momentum locking and preservation of weak band inversion in the gapless surface state, suggesting the nontrivial topological surface states in the presence of the stacking fault. Our findings provide a plausible elucidation to the long-standing conundrum of reconciling the observation of gapped and gapless states on MBT surfaces.
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Affiliation(s)
- Jeonghwan Ahn
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Seoung-Hun Kang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Mina Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jaron T Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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17
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Luo J, Tong Q, Jiang Z, Bai H, Wu J, Liu X, Xie S, Ge H, Zhao Y, Liu Y, Hong M, Shen D, Zhang Q, Liu W, Tang X. Exploring the Epitaxial Growth Kinetics and Anomalous Hall Effect in Magnetic Topological Insulator MnBi 2Te 4 Films. ACS NANO 2023; 17:19022-19032. [PMID: 37732876 DOI: 10.1021/acsnano.3c04626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The discovery of MnBi2Te4-based intrinsic magnetic topological insulators has fueled tremendous interest in condensed matter physics, owing to their potential as an ideal platform for exploring the quantum anomalous Hall effect and other magnetism-topology interactions. However, the fabrication of single-phase MnBi2Te4 films remains a common challenge in the research field. Herein, we present an effective and simple approach for fabricating high-quality, near-stoichiometric MnBi2Te4 films by directly matching the growth rates of intermediate Bi2Te3 and MnTe. Through systematic experimental studies and thermodynamic calculations, we demonstrate that binary phases of Bi2Te3 and MnTe are easily formed during film growth, and the reaction of Bi2Te3 + MnTe → MnBi2Te4 represents the rate-limiting step among all possible reaction paths, which could result in the presence of Bi2Te3 and MnTe impurity phases in the grown MnBi2Te4 films. Moreover, Bi2Te3 and MnTe impurities introduce negative and positive anomalous Hall (AH) components, respectively, in the AH signals of MnBi2Te4 films. Our work suggests that further manipulation of growth parameters should be the essential route for fabricating phase-pure MnBi2Te4 films.
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Affiliation(s)
- Jiangfan Luo
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Qiwei Tong
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Zhicheng Jiang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - Hui Bai
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Jinsong Wu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Xiaolin Liu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Sen Xie
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Haoran Ge
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Yan Zhao
- College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China
- The Institute of Technological Sciences, Wuhan University, Wuhan 430070, China
| | - Yong Liu
- Department of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Min Hong
- Centre for Future Materials, and School of Engineering, University of Southern Queensland, Springfield, Queensland 4300, Australia
| | - Dawei Shen
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Qingjie Zhang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Wei Liu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Xinfeng Tang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
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18
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Abstract
MnBi2Te4, an antiferromagnetic topological insulator, was theoretically predicted to have a gapped surface state on its (111) surface. However, a much smaller gapped or even gapless surface state has been observed experimentally, which is thought to be caused by the defects in MnBi2Te4. Here, we have theoretically identified the antisite MnBi and BiMn as dominant defects and revealed their evolution during the phase transition from MnTe/Bi2Te3 to MnBi2Te4. We found that the complete elimination of MnBi and BiMn defects in MnBi2Te4 by simple annealing is almost impossible due to the high migration barrier in kinetics. Moreover, the gap of the Dirac point-related bands in a MnBi2Te4 monolayer would be eliminated with an increasing concentration of MnBi and BiMn defects, which could explain the experimentally unobserved large-gap surface state in MnBi2Te4. Our results provide an insight into the theoretical understanding of the quality and the experimentally measured topological properties of the synthesized MnBi2Te4.
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Affiliation(s)
- Xi Wu
- Shenzhen Geim Graphene Center and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, People's Republic of China
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Chao Ruan
- Shenzhen Geim Graphene Center and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, People's Republic of China
| | - Peizhe Tang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
- Max Planck Institute for the Structure and Dynamics of Matter and Center for Free Electron Laser Science, Hamburg 22761, Germany
| | - Feiyu Kang
- Shenzhen Geim Graphene Center and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, People's Republic of China
| | - Wenhui Duan
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Institute for Advanced Study, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Beijing 100084, People's Republic of China
| | - Jia Li
- Shenzhen Geim Graphene Center and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, People's Republic of China
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19
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Creation of chiral interface channels for quantized transport in magnetic topological insulator multilayer heterostructures. Nat Commun 2023; 14:770. [PMID: 36765068 PMCID: PMC9918724 DOI: 10.1038/s41467-023-36488-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/01/2023] [Indexed: 02/12/2023] Open
Abstract
One-dimensional chiral interface channels can be created at the boundary of two quantum anomalous Hall (QAH) insulators with different Chern numbers. Such a QAH junction may function as a chiral edge current distributer at zero magnetic field, but its realization remains challenging. Here, by employing an in-situ mechanical mask, we use molecular beam epitaxy to synthesize QAH insulator junctions, in which two QAH insulators with different Chern numbers are connected along a one-dimensional junction. For the junction between Chern numbers of 1 and -1, we observe quantized transport and demonstrate the appearance of the two parallel propagating chiral interface channels along the magnetic domain wall at zero magnetic field. For the junction between Chern numbers of 1 and 2, our quantized transport shows that a single chiral interface channel appears at the interface. Our work lays the foundation for the development of QAH insulator-based electronic and spintronic devices and topological chiral networks.
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20
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Zhang G, Wu H, Zhang L, Yang L, Xie Y, Guo F, Li H, Tao B, Wang G, Zhang W, Chang H. Two-Dimensional Van Der Waals Topological Materials: Preparation, Properties, and Device Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2204380. [PMID: 36135779 DOI: 10.1002/smll.202204380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/23/2022] [Indexed: 06/16/2023]
Abstract
Over the past decade, 2D van der Waals (vdW) topological materials (TMs), including topological insulators and topological semimetals, which combine atomically flat 2D layers and topologically nontrivial band structures, have attracted increasing attention in condensed-matter physics and materials science. These easily cleavable and integrated TMs provide the ideal platform for exploring topological physics in the 2D limit, where new physical phenomena may emerge, and represent a potential to control and investigate exotic properties and device applications in nanoscale topological phases. However, multifaced efforts are still necessary, which is the prerequisite for the practical application of 2D vdW TMs. Herein, this review focuses on the preparation, properties, and device applications of 2D vdW TMs. First, three common preparation strategies for 2D vdW TMs are summarized, including single crystal exfoliation, chemical vapor deposition, and molecular beam epitaxy. Second, the origin and regulation of various properties of 2D vdW TMs are introduced, involving electronic properties, transport properties, optoelectronic properties, thermoelectricity, ferroelectricity, and magnetism. Third, some device applications of 2D vdW TMs are presented, including field-effect transistors, memories, spintronic devices, and photodetectors. Finally, some significant challenges and opportunities for the practical application of 2D vdW TMs in 2D topological electronics are briefly addressed.
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Affiliation(s)
- Gaojie Zhang
- Quantum-Nano Matter and Device Lab, Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hao Wu
- Quantum-Nano Matter and Device Lab, Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Liang Zhang
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Li Yang
- Quantum-Nano Matter and Device Lab, Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yuanmiao Xie
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Fei Guo
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Hongda Li
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Boran Tao
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Guofu Wang
- Liuzhou Key Laboratory for New Energy Vehicle Power Lithium Battery, School of Microelectronics and Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Wenfeng Zhang
- Quantum-Nano Matter and Device Lab, Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen, 518000, China
| | - Haixin Chang
- Quantum-Nano Matter and Device Lab, Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen, 518000, China
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21
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Controlled large non-reciprocal charge transport in an intrinsic magnetic topological insulator MnBi 2Te 4. Nat Commun 2022; 13:6191. [PMID: 36261426 PMCID: PMC9582003 DOI: 10.1038/s41467-022-33705-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/28/2022] [Indexed: 11/08/2022] Open
Abstract
Symmetries, quantum geometries and electronic correlations are among the most important ingredients of condensed matters, and lead to nontrivial phenomena in experiments, for example, non-reciprocal charge transport. Of particular interest is whether the non-reciprocal transport can be manipulated. Here, we report the controllable large non-reciprocal charge transport in the intrinsic magnetic topological insulator MnBi2Te4. The current direction relevant resistance is observed at chiral edges, which is magnetically switchable, edge position sensitive and stacking sequence controllable. Applying gate voltage can also effectively manipulate the non-reciprocal response. The observation and manipulation of non-reciprocal charge transport reveals the fundamental role of chirality in charge transport of MnBi2Te4, and pave ways to develop van der Waals spintronic devices by chirality engineering.
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22
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Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators. Proc Natl Acad Sci U S A 2022; 119:e2207681119. [PMID: 36215491 PMCID: PMC9586289 DOI: 10.1073/pnas.2207681119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In intrinsic magnetic topological insulators, Dirac surface-state gaps are prerequisites for quantum anomalous Hall and axion insulating states. Unambiguous experimental identification of these gaps has proved to be a challenge, however. Here, we use molecular beam epitaxy to grow intrinsic MnBi2Te4 thin films. Using scanning tunneling microscopy/spectroscopy, we directly visualize the Dirac mass gap and its disappearance below and above the magnetic order temperature. We further reveal the interplay of Dirac mass gaps and local magnetic defects. We find that, in high defect regions, the Dirac mass gap collapses. Ab initio and coupled Dirac cone model calculations provide insight into the microscopic origin of the correlation between defect density and spatial gap variations. This work provides unambiguous identification of the Dirac mass gap in MnBi2Te4 and, by revealing the microscopic origin of its gap variation, establishes a material design principle for realizing exotic states in intrinsic magnetic topological insulators.
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23
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Topological current divider in a Chern insulator junction. Nat Commun 2022; 13:5967. [PMID: 36216927 PMCID: PMC9550783 DOI: 10.1038/s41467-022-33645-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/21/2022] [Indexed: 11/08/2022] Open
Abstract
A Chern insulator is a two-dimensional material that hosts chiral edge states produced by the combination of topology with time reversal symmetry breaking. Such edge states are perfect one-dimensional conductors, which may exist not only on sample edges, but on any boundary between two materials with distinct topological invariants (or Chern numbers). Engineering of such interfaces is highly desirable due to emerging opportunities of using topological edge states for energy-efficient information transmission. Here, we report a chiral edge-current divider based on Chern insulator junctions formed within the layered topological magnet MnBi2Te4. We find that in a device containing a boundary between regions of different thickness, topological domains with different Chern numbers can coexist. At the domain boundary, a Chern insulator junction forms, where we identify a chiral edge mode along the junction interface. We use this to construct topological circuits in which the chiral edge current can be split, rerouted, or switched off by controlling the Chern numbers of the individual domains. Our results demonstrate MnBi2Te4 as an emerging platform for topological circuits design.
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24
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McLaughlin NJ, Hu C, Huang M, Zhang S, Lu H, Yan GQ, Wang H, Tserkovnyak Y, Ni N, Du CR. Quantum Imaging of Magnetic Phase Transitions and Spin Fluctuations in Intrinsic Magnetic Topological Nanoflakes. NANO LETTERS 2022; 22:5810-5817. [PMID: 35816128 DOI: 10.1021/acs.nanolett.2c01390] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Topological materials featuring exotic band structures, unconventional current flow patterns, and emergent organizing principles offer attractive platforms for the development of next-generation transformative quantum electronic technologies. The family of MnBi2Te4 (Bi2Te3)n materials is naturally relevant in this context due to their nontrivial band topology, tunable magnetism, and recently discovered extraordinary quantum transport behaviors. Despite numerous pioneering studies to date, the local magnetic properties of MnBi2Te4 (Bi2Te3)n remain an open question, hindering a comprehensive understanding of their fundamental material properties. Exploiting nitrogen-vacancy (NV) centers in diamond, we report nanoscale quantum imaging of the magnetic phase transitions and spin fluctuations in exfoliated MnBi4Te7 flakes, revealing the underlying spin transport physics and magnetic domains at the nanoscale. Our results highlight the unique advantage of NV centers in exploring the magnetic properties of emergent quantum materials, opening new opportunities for investigating the interplay between topology and magnetism.
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Affiliation(s)
- Nathan J McLaughlin
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Chaowei Hu
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Mengqi Huang
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Shu Zhang
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Hanyi Lu
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Gerald Q Yan
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
| | - Hailong Wang
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, California 92093, United States
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Ni Ni
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Chunhui Rita Du
- Department of Physics, University of California, San Diego, La Jolla, California 92093, United States
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, California 92093, United States
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25
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Li G, Wu X, Gao Y, Ma X, Hou F, Cheng H, Huang Q, Wu YC, DeCapua MC, Zhang Y, Lin J, Liu C, Huang L, Zhao Y, Yan J, Huang M. Observation of Ultrastrong Coupling between Substrate and the Magnetic Topological Insulator MnBi 2Te 4. NANO LETTERS 2022; 22:3856-3864. [PMID: 35503660 DOI: 10.1021/acs.nanolett.1c04194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The intrinsic magnetic topological insulator MnBi2Te4 has attracted significant interest recently as a promising platform for exploring exotic quantum phenomena. Here we report that, when atomically thin MnBi2Te4 is deposited on a substrate such as silicon oxide or gold, there is a very strong mechanical coupling between the atomic layer and the supporting substrate. This is manifested as an intense low-frequency breathing Raman mode that is present even for monolayer MnBi2Te4. Interestingly, this coupling turns out to be stronger than the interlayer coupling between the MnBi2Te4 atomic layers. We further found that these low-energy breathing modes are highly sensitive to sample degradation, and they become drastically weaker upon ambient air exposure. This is in contrast to the higher energy optical phonon modes which are much more robust, suggesting that the low-energy Raman modes found here can be an effective indicator of sample quality.
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Affiliation(s)
- Gaomin Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Xiaohua Wu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Yifan Gao
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Xiaoming Ma
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Fuchen Hou
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Hanyan Cheng
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Qiaoling Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Yueh-Chun Wu
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Matthew C DeCapua
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Yujun Zhang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Junhao Lin
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Chang Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Li Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
| | - Yue Zhao
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Jun Yan
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Mingyuan Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People's Republic of China
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26
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Ye C, Xie X, Lv W, Huang K, Yang AJ, Jiang S, Liu X, Zhu D, Qiu X, Tong M, Zhou T, Hsu CH, Chang G, Lin H, Li P, Yang K, Wang Z, Jiang T, Renshaw Wang X. Nonreciprocal Transport in a Bilayer of MnBi 2Te 4 and Pt. NANO LETTERS 2022; 22:1366-1373. [PMID: 35073094 DOI: 10.1021/acs.nanolett.1c04756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
MnBi2Te4 (MBT) is the first intrinsic magnetic topological insulator with the interaction of spin-momentum locked surface electrons and intrinsic magnetism, and it exhibits novel magnetic and topological phenomena. Recent studies suggested that the interaction of electrons and magnetism can be affected by the Mn-doped Bi2Te3 phase at the surface due to inevitable structural defects. Here, we report an observation of nonreciprocal transport, that is, current-direction-dependent resistance, in a bilayer composed of antiferromagnetic MBT and nonmagnetic Pt. The emergence of the nonreciprocal response below the Néel temperature confirms a correlation between nonreciprocity and intrinsic magnetism in the surface state of MBT. The angular dependence of the nonreciprocal transport indicates that nonreciprocal response originates from the asymmetry scattering of electrons at the surface of MBT mediated by magnon. Our work provides an insight into nonreciprocity arising from the correlation between magnetism and Dirac surface electrons in intrinsic magnetic topological insulators.
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Affiliation(s)
- Chen Ye
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Xiangnan Xie
- State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, P.R. China
| | - Wenxing Lv
- Physics Laboratory, Industrial Training Center, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, P.R. China
| | - Ke Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Allen Jian Yang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Sicong Jiang
- Department of NanoEngineering and Program of Chemical Engineering, University of California San Diego, La Jolla, California 92093-0448, United States
- Program of Materials Science and Engineering, University of California San Diego, La Jolla, California 92093-0418, United States
| | - Xue Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P.R. China
| | - Dapeng Zhu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, P.R. China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, P.R. China
| | - Xuepeng Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and School of Physics Science and Engineering, Tongji University, Shanghai 200092, P.R. China
| | - Mingyu Tong
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P.R. China
| | - Tong Zhou
- State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, P.R. China
| | - Chuang-Han Hsu
- Insitute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Hsin Lin
- Insitute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Peisen Li
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha 410073, P.R. China
| | - Kesong Yang
- Department of NanoEngineering and Program of Chemical Engineering, University of California San Diego, La Jolla, California 92093-0448, United States
- Program of Materials Science and Engineering, University of California San Diego, La Jolla, California 92093-0418, United States
| | - Zhenyu Wang
- State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, P.R. China
- National Innovation Institute of Defense Technology, Academy of Military Sciences PLA China, Beijing 100010, P.R. China
- Beijing Academy of Quantum Information Sciences, Beijing 100084, P.R. China
| | - Tian Jiang
- State Key Laboratory of High Performance Computing, College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, P.R. China
- Beijing Institute for Advanced Study, National University of Defense Technology, Changsha 410073, P.R. China
| | - Xiao Renshaw Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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27
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Su SH, Chang JT, Chuang PY, Tsai MC, Peng YW, Lee MK, Cheng CM, Huang JCA. Epitaxial Growth and Structural Characterizations of MnBi 2Te 4 Thin Films in Nanoscale. NANOMATERIALS 2021; 11:nano11123322. [PMID: 34947669 PMCID: PMC8703544 DOI: 10.3390/nano11123322] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 11/30/2022]
Abstract
The intrinsic magnetic topological insulator MnBi2Te4 has attracted much attention due to its special magnetic and topological properties. To date, most reports have focused on bulk or flake samples. For material integration and device applications, the epitaxial growth of MnBi2Te4 film in nanoscale is more important but challenging. Here, we report the growth of self-regulated MnBi2Te4 films by the molecular beam epitaxy. By tuning the substrate temperature to the optimal temperature for the growth surface, the stoichiometry of MnBi2Te4 becomes sensitive to the Mn/Bi flux ratio. Excessive and deficient Mn resulted in the formation of a MnTe and Bi2Te3 phase, respectively. The magnetic measurement of the 7 SL MnBi2Te4 film probed by the superconducting quantum interference device (SQUID) shows that the antiferromagnetic order occurring at the Néel temperature 22 K is accompanied by an anomalous magnetic hysteresis loop along the c-axis. The band structure measured by angle-resolved photoemission spectroscopy (ARPES) at 80 K reveals a Dirac-like surface state, which indicates that MnBi2Te4 has topological insulator properties in the paramagnetic phase. Our work demonstrates the key growth parameters for the design and optimization of the synthesis of nanoscale MnBi2Te4 films, which are of great significance for fundamental research and device applications involving antiferromagnetic topological insulators.
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Affiliation(s)
- Shu-Hsuan Su
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Jen-Te Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Pei-Yu Chuang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Ming-Chieh Tsai
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Yu-Wei Peng
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Min Kai Lee
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106335, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Correspondence: (C.-M.C.); (J.-C.A.H.)
| | - Jung-Chung Andrew Huang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (S.-H.S.); (J.-T.C.); (P.-Y.C.); (M.-C.T.); (Y.-W.P.); (M.K.L.)
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Department of Applied Physics, National University of Kaohsiung, Kaohsiung, 811, Taiwan
- Correspondence: (C.-M.C.); (J.-C.A.H.)
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