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Gu K, Zhang X, Liu X, Guo X, Wu Z, Wang S, Song Q, Wang W, Wei L, Liu P, Ma J, Xu Y, Niu W, Pu Y. Exchange Bias Modulated by Antiferromagnetic Spin-Flop Transition in 2D Van der Waals Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307034. [PMID: 38353386 PMCID: PMC11077673 DOI: 10.1002/advs.202307034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/29/2024] [Indexed: 05/09/2024]
Abstract
Exchange bias is extensively studied and widely utilized in spintronic devices, such as spin valves and magnetic tunnel junctions. 2D van der Waals (vdW) magnets, with high-quality interfaces in heterostructures, provide an excellent platform for investigating the exchange bias effect. To date, intrinsic modulation of exchange bias, for instance, via precise manipulation of the magnetic phases of the antiferromagnetic layer, is yet to be fully reached, owing partly to the large exchange fields of traditional bulk antiferromagnets. Herein, motivated by the low-field spin-flop transition of a 2D antiferromagnet, CrPS4, exchange bias is explored by modulating the antiferromagnetic spin-flop phase transition in all-vdW magnetic heterostructures. The results demonstrate that undergoing the spin-flop transition during the field cooling process, the A-type antiferromagnetic ground state of CrPS4 turns into a canted antiferromagnetic one, therefore, it reduces the interfacial magnetic coupling and suppresses the exchange bias. Via conducting different cooling fields, one can select the exchange bias effect switching among the "ON", "depressed", and "OFF" states determined by the spin flop of CrPS4. This work provides an approach to intrinsically modulate the exchange bias in all-vdW heterostructures and paves new avenues to design and manipulate 2D spintronic devices.
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Affiliation(s)
- Kai Gu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Xiaoqian Zhang
- Key Laboratory of Quantum Materials and Devices of Ministry of EducationSchool of PhysicsSoutheast UniversityNanjing211189China
- International Quantum AcademyShenzhen518048China
| | - Xiangjie Liu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Xinlei Guo
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Zhenqi Wu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Shuo Wang
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Qinxin Song
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Wei Wang
- Key Laboratory of Flexible Electronics & Institute of Advanced MaterialsJiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing Tech UniversityNanjing211816China
| | - Lujun Wei
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Ping Liu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
| | - Jingrui Ma
- Key Laboratory of Energy Conversion and Storage TechnologiesSouthern University of Science and TechnologyShenzhen518055China
| | - Yongbing Xu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
- School of Electronic Science and EngineeringNanjing UniversityNanjing210023China
| | - Wei Niu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
- Key Laboratory of Energy Conversion and Storage TechnologiesSouthern University of Science and TechnologyShenzhen518055China
| | - Yong Pu
- New Energy Technology Engineering Laboratory of Jiangsu Province & School of ScienceNanjing University of Posts and TelecommunicationsNanjing210023China
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2
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Xue F, Hou Y, Wang Z, Xu Z, He K, Wu R, Xu Y, Duan W. Tunable quantum anomalous Hall effects in ferromagnetic van der Waals heterostructures. Natl Sci Rev 2024; 11:nwad151. [PMID: 38312389 PMCID: PMC10833467 DOI: 10.1093/nsr/nwad151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/24/2023] [Accepted: 04/03/2023] [Indexed: 02/02/2024] Open
Abstract
The quantum anomalous Hall effect (QAHE) has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers C = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers C = ±3 can be realized in a single material candidate, which is composed of van der Waals (vdW) coupled Bi and MnBi2Te4 monolayers. The switching between different phases of QAHE can be controlled in multiple ways, such as applying strain or (weak) magnetic field or twisting the vdW materials. The prediction of an experimentally available material system hosting robust, highly tunable QAHE will stimulate great research interest in the field. Our work opens a new avenue for the realization of tunable QAHE and provides a practical material platform for the development of topological electronics.
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Affiliation(s)
- Feng Xue
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yusheng Hou
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Center for Neutron Science and Technology, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhe Wang
- State Key Laboratory of Surface Physics, Key Laboratory of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, China
| | - Zhiming Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Ke He
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- 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
| | - Ruqian Wu
- Department of Physics and Astronomy, University of California-Irvine, Irvine, CA 92697, USA
| | - Yong Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
- Tencent Quantum Laboratory, Tencent Technology (Shenzhen) Co. Ltd, Shenzhen 518057, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Wenhui Duan
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- 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
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
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3
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Zhou X, Xu H, Zhang J, Tang L, Chen X, Mao Z. Re-emerging magnetic order in correlated van der Waals antiferromagnet NiPS 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:205803. [PMID: 38295441 DOI: 10.1088/1361-648x/ad24bd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
Van der Waals (vdW) gap is a significant feature that distinguishes vdW magnets from traditional magnets. Manipulating the magnetic properties by changing the vdW gap has been hot topic in condensed matter research. Here we report a re-emerging magnetic order induced by pressure in a correlated vdW antiferromagnetic insulator NiPS3. It is found that the interlayer magnetoresistance (MR) nearly vanishes at the critical pressure where the crystal structure transforms fromC2/mphase to the slidingC2/mphase. On further compression within the slidingC2/mphase, a substantially enhanced MR emerges from low temperature associated with an insulator-to-metal transition, indicating a metallic antiferromagnetic phase. The enhanced re-emerging MR in slidingC2/mphase can be ascribed to the increasing magnetic interaction between neighboring layers due to the vdW gap narrowing. Our results provide important experimental clues for understanding the pressure effects on magnetism in correlated layered materials.
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Affiliation(s)
- Xueli Zhou
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
| | - Haihong Xu
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
| | - Jiang Zhang
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
| | - Lingyun Tang
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
| | - Xi Chen
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
| | - Zhongquan Mao
- School of Physics and Optoelectronics, South China University of Technology, Guangzhou, Guangdong 510641, People's Republic of China
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4
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Zou X, Li R, Chen Z, Dai Y, Huang B, Niu C. Engineering Gapless Edge States from Antiferromagnetic Chern Homobilayer. NANO LETTERS 2024; 24:450-457. [PMID: 38112315 DOI: 10.1021/acs.nanolett.3c04304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
We put forward that stacked Chern insulators with opposite chiralities offer a strategy to achieve gapless helical edge states in two dimensions. We employ the square lattice as an example and elucidate that the gapless chiral and helical edge states emerge in the monolayer and antiferromagnetically stacked bilayer, characterized by Chern number C = - 1 and spin Chern number C S = - 1 , respectively. Particularly, for a topological phase transition to the normal insulator in the stacked bilayer, a band gap closing and reopening procedure takes place accompanied by helical edge states disappearing, where the Chern insulating phase in the monolayer vanishes at the same time. Moreover, EuO is revealed as a suitable candidate for material realization. This work is not only valuable to the research of the quantum anomalous Hall effect but also offers a favorable platform to realize magnetic topologically insulating materials for spintronics applications.
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Affiliation(s)
- Xiaorong Zou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Runhan Li
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Zhiqi Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Chengwang Niu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
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5
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Jin KH, Jiang W, Sethi G, Liu F. Topological quantum devices: a review. NANOSCALE 2023; 15:12787-12817. [PMID: 37490310 DOI: 10.1039/d3nr01288c] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The introduction of the concept of topology into condensed matter physics has greatly deepened our fundamental understanding of transport properties of electrons as well as all other forms of quasi particles in solid materials. It has also fostered a paradigm shift from conventional electronic/optoelectronic devices to novel quantum devices based on topology-enabled quantum device functionalities that transfer energy and information with unprecedented precision, robustness, and efficiency. In this article, the recent research progress in topological quantum devices is reviewed. We first outline the topological spintronic devices underlined by the spin-momentum locking property of topology. We then highlight the topological electronic devices based on quantized electron and dissipationless spin conductivity protected by topology. Finally, we discuss quantum optoelectronic devices with topology-redefined photoexcitation and emission. The field of topological quantum devices is only in its infancy, we envision many significant advances in the near future.
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Affiliation(s)
- Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Wei Jiang
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Gurjyot Sethi
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
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6
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Muñiz Cano B, Ferreiros Y, Pantaleón PA, Dai J, Tallarida M, Figueroa AI, Marinova V, García-Díez K, Mugarza A, Valenzuela SO, Miranda R, Camarero J, Guinea F, Silva-Guillén JA, Valbuena MA. Experimental Demonstration of a Magnetically Induced Warping Transition in a Topological Insulator Mediated by Rare-Earth Surface Dopants. NANO LETTERS 2023. [PMID: 37156508 DOI: 10.1021/acs.nanolett.3c00587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Magnetic topological insulators constitute a novel class of materials whose topological surface states (TSSs) coexist with long-range ferromagnetic order, eventually breaking time-reversal symmetry. The subsequent bandgap opening is predicted to co-occur with a distortion of the TSS warped shape from hexagonal to trigonal. We demonstrate such a transition by means of angle-resolved photoemission spectroscopy on the magnetically rare-earth (Er and Dy) surface-doped topological insulator Bi2Se2Te. Signatures of the gap opening are also observed. Moreover, increasing the dopant coverage results in a tunable p-type doping of the TSS, thereby allowing for a gradual tuning of the Fermi level toward the magnetically induced bandgap. A theoretical model where a magnetic Zeeman out-of-plane term is introduced in the Hamiltonian governing the TSS rationalizes these experimental results. Our findings offer new strategies to control magnetic interactions with TSSs and open up viable routes for the realization of the quantum anomalous Hall effect.
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Affiliation(s)
- Beatriz Muñiz Cano
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
| | - Yago Ferreiros
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
| | - Pierre A Pantaleón
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
| | - Ji Dai
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Massimo Tallarida
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Adriana I Figueroa
- Departament de Física de la Matéria Condensada, Universitat de Barcelona, 08028 Barcelona, Spain
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Barcelona, Spain
| | - Vera Marinova
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, Acad. G. Bontchev, Str. 109, 1113 Sofia, Bulgaria
| | - Kevin García-Díez
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Barcelona, Spain
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Barcelona, Spain
| | - Aitor Mugarza
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Barcelona, Spain
- ICREA Institució Catalana de Recerca i Estudis Avançats, Lluis Companys 23, 08010 Barcelona, Spain
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, 08193 Barcelona, Spain
- ICREA Institució Catalana de Recerca i Estudis Avançats, Lluis Companys 23, 08010 Barcelona, Spain
| | - Rodolfo Miranda
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
- Departamento de Física de la Materia Condensada, Instituto "Nicolás Cabrera" and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Julio Camarero
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
- Departamento de Física de la Materia Condensada, Instituto "Nicolás Cabrera" and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Francisco Guinea
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
- Donostia International Physics Center, Paseo Manuel de Lardizábal 4, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Jose Angel Silva-Guillén
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
| | - Miguel A Valbuena
- Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain
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7
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Li P, Liu N, Zhang J, Chen S, Zhou X, Guo D, Wang C, Ji W, Zhong D. Two-Dimensional Magnetic Semiconducting Heterostructures of Single-Layer CrI 3-CrI 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:19574-19581. [PMID: 37014936 DOI: 10.1021/acsami.2c22494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Single-layer heterostructures of magnetic materials are unique platforms for studying spin-related phenomena in two dimensions (2D) and have promising applications in spintronics and magnonics. Here, we report the fabrication of 2D magnetic lateral heterostructures consisting of single-layer chromium triiodide (CrI3) and chromium diiodide (CrI2). By carefully adjusting the abundance of iodine based on molecular beam epitaxy, single-layer CrI3-CrI2 heterostructures were grown on Au(111) surfaces with nearly atomic-level seamless boundaries. Two distinct types of interfaces, i.e., zigzag and armchair interfaces, have been identified by means of scanning tunneling microscopy. Our scanning tunneling spectroscopy study combined with density functional theory calculations indicates the existence of spin-polarized ground states below and above the Fermi energy localized at the boundary. Both the armchair and zigzag interfaces exhibit semiconducting nanowire behaviors with different spatial distributions of density of states. Our work presents a novel low-dimensional magnetic system for studying spin-related physics with reduced dimensions and designing advanced spintronic devices.
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Affiliation(s)
- Peigen Li
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Nanshu Liu
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, 100872 Beijing, China
| | - Jihai Zhang
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Shenwei Chen
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Xuhan Zhou
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Donghui Guo
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
| | - Cong Wang
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, 100872 Beijing, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, 100872 Beijing, China
| | - Dingyong Zhong
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
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8
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Xu Z, Duan W, Xu Y. Controllable Chirality and Band Gap of Quantum Anomalous Hall Insulators. NANO LETTERS 2023; 23:305-311. [PMID: 36537751 DOI: 10.1021/acs.nanolett.2c04369] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Finding guiding principles to optimize properties of quantum anomalous Hall (QAH) insulators is of pivotal importance to fundamental science and applications. Here, we build a first-principles QAH material database of chirality and band gap, explore microscopic mechanisms determining the QAH material properties, and obtain a general physical picture that can help researchers comprehensively understand the QAH data. Our results reveal that the usually neglected Coulomb exchange is unexpectedly strong in a large class of QAH materials, which is the key to resolve experimental puzzles. Moreover, we identify simple indicators for property evaluation and suggest material design strategies to control QAH chirality and gap by tuning cooperative or competing contributions via magnetic codoping, heterostructuring, spin-orbit proximity, etc. The work is valuable to future research of magnetic topological physics and materials.
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Affiliation(s)
- Zhiming Xu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing100084, China
| | - Wenhui Duan
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing100084, China
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong518057, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing100084, China
- Institute for Advanced Study, Tsinghua University, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Yong Xu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing100084, China
- Tencent Quantum Laboratory, Tencent, Shenzhen, Guangdong518057, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing100084, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama351-0198, Japan
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9
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Zhang H, Zhang J, Zhang Y, Yang W, Wang Y, Xu X, Liu F. A generic dual d-band model for interlayer ferromagnetic coupling in a transition-metal doped MnBi 2Te 4 family of materials. NANOSCALE 2022; 14:13689-13695. [PMID: 36093811 DOI: 10.1039/d2nr03283j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Realization of ferromagnetic (FM) interlayer coupling in magnetic topological insulators (TIs) of the MnBi2Te4 family of materials (MBTs) may pave the way for realizing the high-temperature quantum anomalous Hall effect (high-T QAHE). Here we propose a generic dual d-band (DDB) model to elucidate the energy difference (ΔE = EAFM - EFM) between the AFM and FM coupling in transition-metal (TM)-doped MBTs, where the valence of TMs splits into d-t2g and d-eg sub-bands. Remarkably, the DDB shows that ΔE is universally determined by the relative position of the dopant (X) and Mn d-eg/t2g bands, . If ΔEd > 0, then ΔE > 0 and the desired FM coupling is favored. This surprisingly simple rule is confirmed by first-principles calculations of hole-type 3d and 4d TM dopants. Significantly, by applying the DDB model, we predict the high-T QAHE in the V-doped Mn2Bi2Te5, where the Curie temperature is enhanced by doubling of the MnTe layer, while the topological order mitigated by doping can be restored by strain.
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Affiliation(s)
- Huisheng Zhang
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Jingjing Zhang
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Yaling Zhang
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Wenjia Yang
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Yingying Wang
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Xiaohong Xu
- College of Physics and Electronic Information & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & Research Institute of Materials Science, Shanxi Normal University, Taiyuan, 030031, China.
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
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10
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Zhou J, Zhang W, Lin YC, Cao J, Zhou Y, Jiang W, Du H, Tang B, Shi J, Jiang B, Cao X, Lin B, Fu Q, Zhu C, Guo W, Huang Y, Yao Y, Parkin SSP, Zhou J, Gao Y, Wang Y, Hou Y, Yao Y, Suenaga K, Wu X, Liu Z. Heterodimensional superlattice with in-plane anomalous Hall effect. Nature 2022; 609:46-51. [PMID: 36045238 DOI: 10.1038/s41586-022-05031-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/28/2022] [Indexed: 11/10/2022]
Abstract
Superlattices-a periodic stacking of two-dimensional layers of two or more materials-provide a versatile scheme for engineering materials with tailored properties1,2. Here we report an intrinsic heterodimensional superlattice consisting of alternating layers of two-dimensional vanadium disulfide (VS2) and a one-dimensional vanadium sulfide (VS) chain array, deposited directly by chemical vapour deposition. This unique superlattice features an unconventional 1T stacking with a monoclinic unit cell of VS2/VS layers identified by scanning transmission electron microscopy. An unexpected Hall effect, persisting up to 380 kelvin, is observed when the magnetic field is in-plane, a condition under which the Hall effect usually vanishes. The observation of this effect is supported by theoretical calculations, and can be attributed to an unconventional anomalous Hall effect owing to an out-of-plane Berry curvature induced by an in-plane magnetic field, which is related to the one-dimensional VS chain. Our work expands the conventional understanding of superlattices and will stimulate the synthesis of more extraordinary superstructures.
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Affiliation(s)
- Jiadong Zhou
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China.
| | - Wenjie Zhang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, and Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Yung-Chang Lin
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Jin Cao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Yao Zhou
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Advanced Research Institute of Multidisciplinary Science, and School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Wei Jiang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Huifang Du
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Bijun Tang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jia Shi
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Bingyan Jiang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, and Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China
| | - Xun Cao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Bo Lin
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Qundong Fu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Chao Zhu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Wei Guo
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Yizhong Huang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yuan Yao
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | | | - Jianhui Zhou
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei, China
| | - Yanfeng Gao
- School of Materials Science and Engineering, Shanghai University, Shanghai, China
| | - Yeliang Wang
- School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing, China
| | - Yanglong Hou
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, School of Materials Science and Engineering, Peking University, Beijing, China
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China.
| | - Kazu Suenaga
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan.
| | - Xiaosong Wu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, and Collaborative Innovation Center of Quantum Matter, Peking University, Beijing, China.
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.
- CINTRA CNRS/NTU/THALES, UMI 3288, Singapore, Singapore.
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore.
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11
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Li Q, Trang CX, Wu W, Hwang J, Cortie D, Medhekar N, Mo SK, Yang SA, Edmonds MT. Large Magnetic Gap in a Designer Ferromagnet-Topological Insulator-Ferromagnet Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107520. [PMID: 35261089 DOI: 10.1002/adma.202107520] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Combining magnetism and nontrivial band topology gives rise to quantum anomalous Hall (QAH) insulators and exotic quantum phases such as the QAH effect where current flows without dissipation along quantized edge states. Inducing magnetic order in topological insulators via proximity to a magnetic material offers a promising pathway toward achieving the QAH effect at a high temperature for lossless transport applications. One promising architecture involves a sandwich structure comprising two single-septuple layers (1SL) of MnBi2 Te4 (a 2D ferromagnetic insulator) with ultrathin few quintuple layer (QL) Bi2 Te3 in the middle, and it is predicted to yield a robust QAH insulator phase with a large bandgap greater than 50 meV. Here, the growth of a 1SL MnBi2 Te4 /4QL Bi2 Te3 /1SL MnBi2 Te4 heterostructure via molecular beam epitaxy is demonstrated and the electronic structure probed using angle-resolved photoelectron spectroscopy. Strong hexagonally warped massive Dirac fermions and a bandgap of 75 ± 15 meV are observed. The magnetic origin of the gap is confirmed by the observation of the exchange-Rashba effect, as well as the vanishing bandgap above the Curie temperature, in agreement with density functional theory calculations. These findings provide insights into magnetic proximity effects in topological insulators and reveal a promising platform for realizing the QAH effect at elevated temperatures.
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Affiliation(s)
- Qile Li
- School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia
- ARC Centre for Future Low Energy Electronics Technologies, Monash University, Clayton, VIC, 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Chi Xuan Trang
- School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia
- ARC Centre for Future Low Energy Electronics Technologies, Monash University, Clayton, VIC, 3800, Australia
| | - Weikang Wu
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Jinwoong Hwang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - David Cortie
- Australian Nuclear Science and Technology Organization, Lucas Heights, NSW, 2234, Australia
- Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Nikhil Medhekar
- ARC Centre for Future Low Energy Electronics Technologies, Monash University, Clayton, VIC, 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Mark T Edmonds
- School of Physics and Astronomy, Monash University, Clayton, VIC, 3800, Australia
- ARC Centre for Future Low Energy Electronics Technologies, Monash University, Clayton, VIC, 3800, Australia
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12
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Yu S, Tang J, Wang Y, Xu F, Li X, Wang X. Recent advances in two-dimensional ferromagnetism: strain-, doping-, structural- and electric field-engineering toward spintronic applications. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:140-160. [PMID: 35185390 PMCID: PMC8856075 DOI: 10.1080/14686996.2022.2030652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/03/2022] [Accepted: 01/09/2022] [Indexed: 05/27/2023]
Abstract
Since the first report on truly two-dimensional (2D) magnetic materials in 2017, a wide variety of merging 2D magnetic materials with unusual physical characteristics have been discovered and thus provide an effective platform for exploring the associated novel 2D spintronic devices, which have been made significant progress in both theoretical and experimental studies. Herein, we make a comprehensive review on the recent scientific endeavors and advances on the various engineering strategies on 2D ferromagnets, such as strain-, doping-, structural- and electric field-engineering, toward practical spintronic applications, including spin tunneling junctions, spin field-effect transistors and spin logic gate, etc. In the last, we discuss on current challenges and future opportunities in this field, which may provide useful guidelines for scientists who are exploring the fundamental physical properties and practical spintronic devices of low-dimensional magnets.
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Affiliation(s)
- Sheng Yu
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Junyu Tang
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Yu Wang
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Feixiang Xu
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xinzhong Wang
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
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13
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Fang X, Zhou B, Sun N, Fu L, Wang X. Valley splitting and magnetic anisotropy in two-dimensional VI 3/MSe 2 (M = W, Mo) heterostructures. Phys Chem Chem Phys 2022; 24:4374-4383. [PMID: 35112682 DOI: 10.1039/d1cp05135k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
As a new van der Waals ferromagnetic material, VI3 can be used to lift the valley degeneracy of transition metal dichalcogenides at the K' and K points. Here, the electronic structure and magnetic anisotropy of the VI3/MSe2 (M = W, Mo) heterostructures are studied. The VI3/WSe2 heterostructure is semiconducting with a band gap of 0.26 eV, while the VI3/MoSe2 heterostructure is metallic. Considering the spin-orbit-coupling, a maximum valley splitting of 3.1 meV appears in the VI3/WSe2 heterostructure. The biaxial strain can tune the valley splitting and magnetic anisotropy of VI3/MSe2 heterostructures. In the VI3/WSe2 heterostructure, which has the most stable stacking, valley splitting can be increased from 1.8 meV at 4% compressive strain to 3.1 meV at 4% tensile strain. At a biaxial strain of -2% to 4%, the VI3/WSe2 heterostructure maintains a small perpendicular magnetic anisotropy, while the VI3/MoSe2 heterostructure shows in-plane magnetic anisotropy under different strains. The significantly tunable electronic structure and magnetic anisotropy under biaxial strain suggest that the VI3/MSe2 heterostructures have potential applications in spintronic devices.
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Affiliation(s)
- Xiaotian Fang
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Baozeng Zhou
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Nan Sun
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Luqian Fu
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Xiaocha Wang
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
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14
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Atomically Thin 2D van der Waals Magnetic Materials: Fabrications, Structure, Magnetic Properties and Applications. COATINGS 2022. [DOI: 10.3390/coatings12020122] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two-dimensional (2D) van der Waals (vdW) magnetic materials are considered to be ideal candidates for the fabrication of spintronic devices because of their low dimensionality, allowing the quantization of electronic states and more degrees of freedom for device modulation. With the discovery of few-layer Cr2Ge2Te6 and monolayer CrI3 ferromagnets, the magnetism of 2D vdW materials is becoming a research focus in the fields of material science and physics. In theory, taking the Heisenberg model with finite-range exchange interactions as an example, low dimensionality and ferromagnetism are in competition. In other words, it is difficult for 2D materials to maintain their magnetism. However, the introduction of anisotropy in 2D magnetic materials enables the realization of long-range ferromagnetic order in atomically layered materials, which may offer new effective means for the design of 2D ferromagnets with high Curie temperature. Herein, current advances in the field of 2D vdW magnetic crystals, as well as intrinsic and induced ferromagnetism or antiferromagnetism, physical properties, device fabrication, and potential applications, are briefly summarized and discussed.
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15
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He QL, Hughes TL, Armitage NP, Tokura Y, Wang KL. Topological spintronics and magnetoelectronics. NATURE MATERIALS 2022; 21:15-23. [PMID: 34949869 DOI: 10.1038/s41563-021-01138-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 09/21/2021] [Indexed: 05/08/2023]
Abstract
Topological electronic materials, such as topological insulators, are distinct from trivial materials in the topology of their electronic band structures that lead to robust, unconventional topological states, which could bring revolutionary developments in electronics. This Perspective summarizes developments of topological insulators in various electronic applications including spintronics and magnetoelectronics. We group and analyse several important phenomena in spintronics using topological insulators, including spin-orbit torque, the magnetic proximity effect, interplay between antiferromagnetism and topology, and the formation of topological spin textures. We also outline recent developments in magnetoelectronics such as the axion insulator and the topological magnetoelectric effect observed using different topological insulators.
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Affiliation(s)
- Qing Lin He
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
| | - Taylor L Hughes
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - N Peter Armitage
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Tokyo College, University of Tokyo, Tokyo, Japan
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, USA.
- Center of Quantum Sciences and Engineering, University of California, Los Angeles, CA, USA.
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16
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Abstract
2D layered materials with diverse exciting properties have recently attracted tremendous interest in the scientific community. Layered topological insulator Bi2Se3 comes into the spotlight as an exotic state of quantum matter with insulating bulk states and metallic Dirac-like surface states. Its unique crystal and electronic structure offer attractive features such as broadband optical absorption, thickness-dependent surface bandgap and polarization-sensitive photoresponse, which enable 2D Bi2Se3 to be a promising candidate for optoelectronic applications. Herein, we present a comprehensive summary on the recent advances of 2D Bi2Se3 materials. The structure and inherent properties of Bi2Se3 are firstly described and its preparation approaches (i.e., solution synthesis and van der Waals epitaxy growth) are then introduced. Moreover, the optoelectronic applications of 2D Bi2Se3 materials in visible-infrared detection, terahertz detection, and opto-spintronic device are discussed in detail. Finally, the challenges and prospects in this field are expounded on the basis of current development.
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Affiliation(s)
- Fakun K. Wang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Sijie J. Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Tianyou Y. Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
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17
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Liu J, Hesjedal T. Magnetic Topological Insulator Heterostructures: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2102427. [PMID: 34665482 DOI: 10.1002/adma.202102427] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.
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Affiliation(s)
- Jieyi Liu
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
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18
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Li P, You Y, Huang K, Luo W. Quantum anomalous Hall effect in Cr 2Ge 2Te 6/Bi 2Se 3/Cr 2Ge 2Te 6heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:465003. [PMID: 34433141 DOI: 10.1088/1361-648x/ac2117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Currently, quantum anomalous Hall (QAH) effect can only be observed at very low temperatures, which severely hinders its utilization from spintronics to quantum computation. Finding or predicting new systems supporting QAH effect at high temperatures remains essential and challenging. This work presents first-principles studies on the proximity effect between Bi2Se3slabs and Cr2Ge2Te6(CGT) layers, reporting that Chern insulators are available in CGT/Bi2Se3/CGT heterostructures. If the sandwiched Bi2Se3slab is 4 quintuple layers (QLs) or thicker, the Chern insulating state is robust against the interfacial stacking manner. If the Bi2Se3slab is only 2 or 3 QLs, the CrBi- and CrH-aligned heterostructures are also Chern insulators, while the CrSe-aligned ones are trivial. The Chern insulators support the Hall conductivityσxy=e2/hand have energy gaps ranging from 3 to 20 meV, implying QAH effect at higher temperatures. An effective model Hamiltonian is introduced to understand the topological phase of the heterostructures.
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Affiliation(s)
- Ping Li
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Yuwei You
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Kai Huang
- Key Laboratory of Advanced Electronic Materials and Devices, School of Mathematics and Physics, Anhui Jianzhu University, Hefei, 230601, People's Republic of China
| | - Weidong Luo
- Key Laboratory of Artificial Structures and Quantum Control, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
- Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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19
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Bhattacharyya S, Akhgar G, Gebert M, Karel J, Edmonds MT, Fuhrer MS. Recent Progress in Proximity Coupling of Magnetism to Topological Insulators. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007795. [PMID: 34185344 DOI: 10.1002/adma.202007795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/11/2021] [Indexed: 05/08/2023]
Abstract
Inducing long-range magnetic order in 3D topological insulators can gap the Dirac-like metallic surface states, leading to exotic new phases such as the quantum anomalous Hall effect or the axion insulator state. These magnetic topological phases can host robust, dissipationless charge and spin currents or unique magnetoelectric behavior, which can be exploited in low-energy electronics and spintronics applications. Although several different strategies have been successfully implemented to realize these states, to date these phenomena have been confined to temperatures below a few Kelvin. This review focuses on one strategy: inducing magnetic order in topological insulators by proximity of magnetic materials, which has the capability for room temperature operation, unlocking the potential of magnetic topological phases for applications. The unique advantages of this strategy, the important physical mechanisms facilitating magnetic proximity effect, and the recent progress to achieve, understand, and harness proximity-coupled magnetic order in topological insulators are discussed. Some emerging new phenomena and applications enabled by proximity coupling of magnetism and topological materials, such as skyrmions and the topological Hall effect, are also highlighted, and the authors conclude with an outlook on remaining challenges and opportunities in the field.
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Affiliation(s)
- Semonti Bhattacharyya
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Golrokh Akhgar
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Matthew Gebert
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Julie Karel
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Mark T Edmonds
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Michael S Fuhrer
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
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20
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Perez-Piskunow PM, Roche S. Hinge Spin Polarization in Magnetic Topological Insulators Revealed by Resistance Switch. PHYSICAL REVIEW LETTERS 2021; 126:167701. [PMID: 33961483 DOI: 10.1103/physrevlett.126.167701] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
We report on the possibility of detecting hinge spin polarization in magnetic topological insulators by resistance measurements. By implementing a three-dimensional model of magnetic topological insulators into a multiterminal device with ferromagnetic contacts near the top surface, local spin features of the chiral edge modes are unveiled. We find local spin polarization at the hinges that inverts the sign between the top and bottom surfaces. At the opposite edge, the topological state with inverted spin polarization propagates in the reverse direction. A large resistance switch between forward and backward propagating states is obtained, driven by the matching between the spin polarized hinges and the ferromagnetic contacts. This feature is general to the ferromagnetic, antiferromagnetic, and canted antiferromagnetic phases, and enables the design of spin-sensitive devices, with the possibility of reversing the hinge spin polarization of the currents.
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Affiliation(s)
- Pablo M Perez-Piskunow
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain and ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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21
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Guo Y, Zhang Y, Zhou Z, Zhang X, Wang B, Yuan S, Dong S, Wang J. Spin-constrained optoelectronic functionality in two-dimensional ferromagnetic semiconductor heterojunctions. MATERIALS HORIZONS 2021; 8:1323-1333. [PMID: 34821925 DOI: 10.1039/d0mh01480j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) engineering has brought about many extraordinary and new physics concepts and potential applications. Herein, we propose a new type of spin-constrained optoelectronic device developed using 2D ferromagnetic semiconductor heterostructures (FMSs). It is based on a photoexcited double-band-edge transition model, involved coupling between the interlayer magnetic order and the spin-polarized band structure and can achieve the reversible switch of band alignment via reversal of magnetization. We demonstrate that such a unique magnetic optoelectronic device can be realized with a CrBr3/CrCl3 heterojunction and other 2D FMS heterojunctions that have the same direction as the easy magnetization axis and have a switchable band alignment that allows reconfiguration. This study opens a new application window for 2D vdW heterostructures and enables the possibility for fully vdW-based ultra-compact spintronics devices.
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Affiliation(s)
- Yilv Guo
- School of Physics, Southeast University, Nanjing 211189, China.
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22
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Zhang J, Guo Y, Li P, Wang J, Zhou S, Zhao J, Guo D, Zhong D. Imaging Vacancy Defects in Single-Layer Chromium Triiodide. J Phys Chem Lett 2021; 12:2199-2205. [PMID: 33630596 DOI: 10.1021/acs.jpclett.1c00112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
As a van der Waals magnetic semiconductor, chromium triiodide (CrI3) is widely considered for its high research value and potential applications. Defects in CrI3 are inevitably present and significantly alter the material properties. However, experimental identification of defects of CrI3 at the atomic level is still lacking. Here for the first time, we carried out a scanning tunneling microscopy (STM) study and density functional theory calculations to explore the intrinsic defects in monolayer CrI3 grown by molecular beam epitaxy. The three most common types of intrinsic point defects, i.e., I vacancy (VI), Cr vacancy (VCr), and multiatom CrI3 vacancy (VCrI3) with distinct spatial distributions of the localized defect states, are identified and characterized by high-resolution STM. Moreover, defect concentrations are estimated based on our experiments, which agree with the calculated formation energies. Our findings provide vital knowledge on the types, concentrations, electronic structures, and migration mechanism of the intrinsic point defects in monolayer CrI3 for future defect engineering of this novel 2D magnet.
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Affiliation(s)
- Jihai Zhang
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Yu Guo
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, 116024 Dalian, China
| | - Peigen Li
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Jun Wang
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
| | - Si Zhou
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, 116024 Dalian, China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, 116024 Dalian, China
| | - Donghui Guo
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
| | - Dingyong Zhong
- School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
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23
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Chen L, Jiang C, Yang M, Hu T, Meng Y, Lei J, Zhang M. Magnetism and electronic structures of bismuth (stannum) films at the CrI 3 (CrBr 3) interface. Phys Chem Chem Phys 2021; 23:4255-4261. [PMID: 33586751 DOI: 10.1039/d0cp05531j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From first-principles calculations, the magnetism and electronic structures of bilayer bismuth (stannum) films at the monolayer CrI3 (CrBr3) interface are studied. The Curie temperature (TC) of CrX3 (X = Br, I) can be enhanced by coupling bilayer bismuth (Bi) with van der Waals (vdW) heterostructures. The n-doping of CrX3, induced by interlayer charge-transfer from the Bi film, leads to the enhancement of TC. The quantum spin Hall phases of bilayer bismuth and stannum films are destroyed by the magnetic substrate. Although the interface system of the bilayer stannum (Sn) film on a CrBr3 monolayer shows a band gap (57 meV), the inexistence of edge states with valence and conduction bands connected across the insulating gap is a manifestation of the trivial state without the feature of quantized anomalous Hall effect in the interface. The percentage reduction of the corresponding work function is 22.6%, 12.7%, 25.4% and 16.5% for Bi/CrI3, Sn/CrI3, Bi/CrBr3 and Sn/CrBr3 interface systems, respectively. Our findings demonstrate that the Bi(Sn)-CrI3(CrBr3) interface system with vdW engineering is an efficient way to tune magnetism and electronic structures, which is of importance for future applications in spintronics and nanoelectronics devices.
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Affiliation(s)
- Li Chen
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China. and Institute of Condensed Matter Physics, Linyi University, Shandong 276000, China
| | - Chuan Jiang
- Department of Data Acquisition, National Instruments, Shanghai 201204, China.
| | - Maoyou Yang
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China.
| | - Tao Hu
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China.
| | - Yan Meng
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China.
| | - Jie Lei
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China.
| | - Mingjian Zhang
- School of Electronic and Information Engineering (Department of Physics), Qilu University of Technology, Jinan 250353, China.
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Gong L, Zhang C, Nie A, Lin C, Zhang H, Gao C, Wang M, Zhang X, Han N, Su H, Lin C, Jin Y, Zhang C, Zhang X, Dai JF, Cheng Y, Huang W. Epitaxial growth of large-grain-size ferromagnetic monolayer CrI 3 for valley Zeeman splitting enhancement. NANOSCALE 2021; 13:2955-2962. [PMID: 33506851 DOI: 10.1039/d0nr08248a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) magnetic CrI3 has received considerable research attention because of its intrinsic features, including insulation, Ising ferromagnetism, and stacking-order-dependent magnetism, as well as potential in spintronic applications. However, the current strategy for the production of ambient-unstable CrI3 thin layer is limited to mechanical exfoliation, which normally suffers from uncontrollable layer thickness, small size, and low yet unpredictable yield. Here, via a confined vapor epitaxy (CVE) method, we demonstrate the mass production of flower-like CrI3 monolayers on mica. Interestingly, we discovered the crucial role of K ions on the mica surface in determining the morphology of monolayer CrI3, reacting with precursors to form a KIx buffer layer. Meanwhile, the transport agent affects the thickness and size of the as-grown CrI3. Moreover, the Curie temperature of CrI3 is greatly affected by the interaction between CrI3 and the substrate. The monolayer CrI3 on mica could act as a magnetic substrate for valley Zeeman splitting enhancement of WSe2. We reckon our work represents a major advancement in the mass production of monolayer 2D CrI3 and anticipate that our growth strategy may be extended to other transition metal halides.
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Affiliation(s)
- Lipeng Gong
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China.
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Chu J, Wang Y, Wang X, Hu K, Rao G, Gong C, Wu C, Hong H, Wang X, Liu K, Gao C, Xiong J. 2D Polarized Materials: Ferromagnetic, Ferrovalley, Ferroelectric Materials, and Related Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004469. [PMID: 33325574 DOI: 10.1002/adma.202004469] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/21/2020] [Indexed: 06/12/2023]
Abstract
The emergence of 2D polarized materials, including ferromagnetic, ferrovalley, and ferroelectric materials, has demonstrated unique quantum behaviors at atomic scales. These polarization behaviors are tightly bonded to the new degrees of freedom (DOFs) for next generation information storage and processing, which have been dramatically developed in the past few years. Here, the basic 2D polarized materials system and related devices' application in spintronics, valleytronics, and electronics are reviewed. Specifically, the underlying physical mechanism accompanied with symmetry broken theory and the modulation process through heterostructure engineering are highlighted. These summarized works focusing on the 2D polarization would continue to enrich the cognition of 2D quantum system and promising practical applications.
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Affiliation(s)
- Junwei Chu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yang Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Xuepeng Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Kai Hu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Gaofeng Rao
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Chuanhui Gong
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Chunchun Wu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Hao Hong
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing, 100871, China
| | - Xianfu Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing, 100871, China
| | - Chunlei Gao
- State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), Department of Physics, and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China
| | - Jie Xiong
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
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Lu S, Zhou Q, Guo Y, Zhang Y, Wu Y, Wang J. Coupling a Crystal Graph Multilayer Descriptor to Active Learning for Rapid Discovery of 2D Ferromagnetic Semiconductors/Half-Metals/Metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002658. [PMID: 32538514 DOI: 10.1002/adma.202002658] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/09/2020] [Indexed: 05/27/2023]
Abstract
2D ferromagnetic (FM) semiconductors/half-metals/metals are the key materials toward next-generation spintronic devices. However, such materials are still rather rare and the material search space is too large to explore exhaustively. Here, an adaptive framework to accelerate the discovery of 2D intrinsic FM materials is developed, by combining advanced machine-learning (ML) techniques with high-throughput density functional theory calculations. Successfully, about 90 intrinsic FM materials with desirable bandgap and excellent thermodynamic stability are screened out and a database containing 1459 2D magnetic materials is set up. To improve the performance of ML models on small-scale datasets like diverse 2D materials, a crystal graph multilayer descriptor using the elemental property is proposed, with which ML models achieve prediction accuracy over 90% on thermodynamic stability, magnetism, and bandgap. This study not only provides dozens of compelling FM candidates for future spintronics, but also paves a feasible route for ML-based rapid screening of diverse structures and/or complex properties.
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Affiliation(s)
- Shuaihua Lu
- School of Physics, Southeast University, Nanjing, 211189, China
| | - Qionghua Zhou
- School of Physics, Southeast University, Nanjing, 211189, China
| | - Yilv Guo
- School of Physics, Southeast University, Nanjing, 211189, China
| | - Yehui Zhang
- School of Physics, Southeast University, Nanjing, 211189, China
| | - Yilei Wu
- School of Physics, Southeast University, Nanjing, 211189, China
| | - Jinlan Wang
- School of Physics, Southeast University, Nanjing, 211189, China
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Liang SJ, Cheng B, Cui X, Miao F. Van der Waals Heterostructures for High-Performance Device Applications: Challenges and Opportunities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903800. [PMID: 31608514 DOI: 10.1002/adma.201903800] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/22/2019] [Indexed: 06/10/2023]
Abstract
The discovery of two-dimensional (2D) materials with unique electronic, superior optoelectronic, or intrinsic magnetic order has triggered worldwide interest in the fields of material science, condensed matter physics, and device physics. Vertically stacking 2D materials with distinct electronic and optical as well as magnetic properties enables the creation of a large variety of van der Waals heterostructures. The diverse properties of the vertical heterostructures open unprecedented opportunities for various kinds of device applications, e.g., vertical field-effect transistors, ultrasensitive infrared photodetectors, spin-filtering devices, and so on, which are inaccessible in conventional material heterostructures. Here, the current status of vertical heterostructure device applications in vertical transistors, infrared photodetectors, and spintronic memory/transistors is reviewed. The relevant challenges for achieving high-performance devices are presented. An outlook into the future development of vertical heterostructure devices with integrated electronic and optoelectronic as well as spintronic functionalities is also provided.
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Affiliation(s)
- Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Bin Cheng
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Xinyi Cui
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210046, China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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Fu H, Liu CX, Yan B. Exchange bias and quantum anomalous nomalous Hall effect in the MnBi 2Te 4/CrI 3 heterostructure. SCIENCE ADVANCES 2020; 6:eaaz0948. [PMID: 32181356 PMCID: PMC7060064 DOI: 10.1126/sciadv.aaz0948] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/11/2019] [Indexed: 05/31/2023]
Abstract
The layered antiferromagnetic MnBi2Te4 films have been proposed to be an intrinsic quantum anomalous Hall (QAH) insulator with a large gap. It is crucial to open a magnetic gap of surface states. However, recent experiments have observed gapless surface states, indicating the absence of out-of-plane surface magnetism, and thus, the quantized Hall resistance can only be achieved at the magnetic field above 6 T. We propose to induce out-of-plane surface magnetism of MnBi2Te4 films via the magnetic proximity with magnetic insulator CrI3. A strong exchange bias of ∼40 meV originates from the long Cr-eg orbital tails that hybridize strongly with Te p orbitals. By stabilizing surface magnetism, the QAH effect can be realized in the MnBi2Te4/CrI3 heterostructure. Moreover, the high-Chern number QAH state can be achieved by controlling external electric gates. Thus, the MnBi2Te4/CrI3 heterostructure provides a promising platform to realize the electrically tunable zero-field QAH effect.
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Affiliation(s)
- Huixia Fu
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Chao-Xing Liu
- Department of Physics, the Pennsylvania State University, University Park, PA 16802, USA
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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Lu Y, Fei R, Lu X, Zhu L, Wang L, Yang L. Artificial Multiferroics and Enhanced Magnetoelectric Effect in van der Waals Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6243-6249. [PMID: 31910613 DOI: 10.1021/acsami.9b19320] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Multiferroic materials with coupled ferroelectric (FE) and ferromagnetic (FM) properties are important for multifunctional devices because of their potential ability of controlling magnetism via electric field and vice versa. The recent discoveries of two-dimensional (2D) FM and FE materials have ignited tremendous research interest and aroused hope to search for 2D multiferroics. However, intrinsic 2D multiferroic materials and, particularly, those with strong magnetoelectric couplings are still rare to date. In this paper, using first-principles simulations, we propose artificial 2D multiferroics via a van der Waals (vdW) heterostructure formed by FM bilayer chromium triiodide (CrI3) and FE monolayer Sc2CO2. In addition to the coexistence of ferromagnetism and ferroelectricity, our calculations show that, by switching the electric polarization of Sc2CO2, we can tune the interlayer magnetic couplings of bilayer CrI3 between the FM and antiferromagnetic states. We further reveal that such a strong magnetoelectric effect is from a dramatic change of the band alignment induced by the strong built-in electric polarization in Sc2CO2 and the subsequent change of the interlayer magnetic coupling of bilayer CrI3. These artificial multiferroics and enhanced magnetoelectric effect give rise to realizing multifunctional nanoelectronics by vdW heterostructures.
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Affiliation(s)
- Yan Lu
- Department of Physics and Institute of Materials Science and Engineering , Washington University, St. Louis , St. Louis , Missouri 63130 , United States
- Department of Physics , Nanchang University , Nanchang 330031 , China
| | - Ruixiang Fei
- Department of Physics and Institute of Materials Science and Engineering , Washington University, St. Louis , St. Louis , Missouri 63130 , United States
| | - Xiaobo Lu
- Department of Physics and Institute of Materials Science and Engineering , Washington University, St. Louis , St. Louis , Missouri 63130 , United States
| | - Linghan Zhu
- Department of Physics and Institute of Materials Science and Engineering , Washington University, St. Louis , St. Louis , Missouri 63130 , United States
| | - Li Wang
- Department of Physics , Nanchang University , Nanchang 330031 , China
| | - Li Yang
- Department of Physics and Institute of Materials Science and Engineering , Washington University, St. Louis , St. Louis , Missouri 63130 , United States
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