1
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Zheng XY, Channa S, Riddiford LJ, Wisser JJ, Mahalingam K, Bowers CT, McConney ME, N'Diaye AT, Vailionis A, Cogulu E, Ren H, Galazka Z, Kent AD, Suzuki Y. Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping. Nat Commun 2023; 14:4918. [PMID: 37582804 PMCID: PMC10427713 DOI: 10.1038/s41467-023-40733-9] [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: 02/19/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Ultra-thin films of low damping ferromagnetic insulators with perpendicular magnetic anisotropy have been identified as critical to advancing spin-based electronics by significantly reducing the threshold for current-induced magnetization switching while enabling new types of hybrid structures or devices. Here, we have developed a new class of ultra-thin spinel structure Li0.5Al1.0Fe1.5O4 (LAFO) films on MgGa2O4 (MGO) substrates with: 1) perpendicular magnetic anisotropy; 2) low magnetic damping and 3) the absence of degraded or magnetic dead layers. These films have been integrated with epitaxial Pt spin source layers to demonstrate record low magnetization switching currents and high spin-orbit torque efficiencies. These LAFO films on MGO thus combine all of the desirable properties of ferromagnetic insulators with perpendicular magnetic anisotropy, opening new possibilities for spin based electronics.
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Affiliation(s)
- Xin Yu Zheng
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
| | - Sanyum Channa
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Lauren J Riddiford
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
| | - Jacob J Wisser
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | | | - Cynthia T Bowers
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Michael E McConney
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Arturas Vailionis
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Kaunas University of Technology, Studentu Street 50, LT-51368, Kaunas, Lithuania
| | - Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Haowen Ren
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Zbigniew Galazka
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Yuri Suzuki
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
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2
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Alahmed L, Zhang X, Wen J, Xiong Y, Li Y, Zhang LC, Lux F, Freimuth F, Mahdi M, Mokrousov Y, Novosad V, Kwok WK, Yu D, Zhang W, Lee YS, Li P. Evidence of Magnon-Mediated Orbital Magnetism in a Quasi-2D Topological Magnon Insulator. NANO LETTERS 2022; 22:5114-5119. [PMID: 35699946 DOI: 10.1021/acs.nanolett.2c00562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We explore spin dynamics in Cu(1,3-bdc), a quasi-2D topological magnon insulator. The results show that the thermal evolution of the Landé g factor (g) is anisotropic: gin-plane decreases while gout-of-plane increases with increasing temperature T. Moreover, the anisotropy of the g factor (Δg) and the anisotropy of saturation magnetization (ΔMs) are correlated below 4 K, but they diverge above 4 K. We show that the electronic orbital moment contributes to the g anisotropy at lower T, while the topological orbital moment induced by thermally excited spin chirality dictates the g anisotropy at higher T. Our work suggests an interplay among topology, spin chirality, and orbital magnetism in Cu(1,3-bdc).
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Affiliation(s)
- Laith Alahmed
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Xiaoqian Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiajia Wen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yuzan Xiong
- Department of Electrical and Computer Engineering, Oakland University, Rochester, Michigan 48309 United States
| | - Yi Li
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Li-Chuan Zhang
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Fabian Lux
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Frank Freimuth
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Muntasir Mahdi
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Valentine Novosad
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Wai-Kwong Kwok
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wei Zhang
- Department of Physics, Oakland University, Rochester, Michigan 48309 United States
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Young S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
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3
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Ou Y, Yanez W, Xiao R, Stanley M, Ghosh S, Zheng B, Jiang W, Huang YS, Pillsbury T, Richardella A, Liu C, Low T, Crespi VH, Mkhoyan KA, Samarth N. ZrTe 2/CrTe 2: an epitaxial van der Waals platform for spintronics. Nat Commun 2022; 13:2972. [PMID: 35624122 PMCID: PMC9142486 DOI: 10.1038/s41467-022-30738-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 05/16/2022] [Indexed: 11/08/2022] Open
Abstract
The rapid discovery of two-dimensional (2D) van der Waals (vdW) quantum materials has led to heterostructures that integrate diverse quantum functionalities such as topological phases, magnetism, and superconductivity. In this context, the epitaxial synthesis of vdW heterostructures with well-controlled interfaces is an attractive route towards wafer-scale platforms for systematically exploring fundamental properties and fashioning proof-of-concept devices. Here, we use molecular beam epitaxy to synthesize a vdW heterostructure that interfaces two material systems of contemporary interest: a 2D ferromagnet (1T-CrTe2) and a topological semimetal (ZrTe2). We find that one unit-cell (u.c.) thick 1T-CrTe2 grown epitaxially on ZrTe2 is a 2D ferromagnet with a clear anomalous Hall effect. In thicker samples (12 u.c. thick CrTe2), the anomalous Hall effect has characteristics that may arise from real-space Berry curvature. Finally, in ultrathin CrTe2 (3 u.c. thickness), we demonstrate current-driven magnetization switching in a full vdW topological semimetal/2D ferromagnet heterostructure device.
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Affiliation(s)
- Yongxi Ou
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wilson Yanez
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Run Xiao
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Max Stanley
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Supriya Ghosh
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Boyang Zheng
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wei Jiang
- Department of Electrical & Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yu-Sheng Huang
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Timothy Pillsbury
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Anthony Richardella
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Chaoxing Liu
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Tony Low
- Department of Electrical & Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
- School of Physics & Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Vincent H Crespi
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - K Andre Mkhoyan
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Nitin Samarth
- Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA.
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4
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Xu Z, Liu Q, Ji Y, Li X, Li J, Wang J, Chen L. Strain-Tunable Interfacial Dzyaloshinskii-Moriya Interaction and Spin-Hall Topological Hall Effect in Pt/Tm 3Fe 5O 12 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16791-16799. [PMID: 35362315 DOI: 10.1021/acsami.1c22942] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The interfacial Dzyaloshinskii-Moriya interaction (DMI) in heavy-metal/ferromagnet heterostructures enables to stabilize and manipulate novel topological spin textures, such as skyrmions, which arise as potential logic and memory devices for future information technology. Along these lines, we study in this work the topological spin textures in the films of magnetic insulators by detecting the spin-Hall topological Hall effect (SH-THE). The SH-THE presents obvious dependence of epitaxial strain in Pt/Tm3Fe5O12 (TmIG) bilayers deposited on a series of (111)-oriented garnet substrates, indicating that the topological spin textures can be tuned by epitaxial strain in this system. It is interesting to note that the room-temperature and low-field peak of SH-THE is also recorded within the Pt/TmIG bilayer configuration. We have also examined the interfacial DMI in the Pt/TmIG bilayers by an extended droplet model. The results indicate that the epitaxial strain can effectively change the interfacial DMI in this system, suggesting that the strain-induced modification of the interfacial DMI is the driving force for the SH-THE and topological spin textures in the Pt/TmIG bilayers. Our outcomes open new exciting avenues and opportunities in engineering chiral magnetism and examining the future skyrmion technology in magnetic insulators through the application of epitaxial strain.
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Affiliation(s)
- Zedong Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Qi Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yanjiang Ji
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xiaowen Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Junxue Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Junling Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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5
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Zou WJ, Guo MX, Wong JF, Huang ZP, Chia JM, Chen WN, Wang SX, Lin KY, Young LB, Lin YHG, Yahyavi M, Wu CT, Jeng HT, Lee SF, Chang TR, Hong M, Kwo J. Enormous Berry-Curvature-Based Anomalous Hall Effect in Topological Insulator (Bi,Sb) 2Te 3 on Ferrimagnetic Europium Iron Garnet beyond 400 K. ACS NANO 2022; 16:2369-2380. [PMID: 35099945 DOI: 10.1021/acsnano.1c08663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
To realize the quantum anomalous Hall effect (QAHE) at elevated temperatures, the approach of magnetic proximity effect (MPE) was adopted to break the time-reversal symmetry in the topological insulator (Bi0.3Sb0.7)2Te3 (BST) based heterostructures with a ferrimagnetic insulator europium iron garnet (EuIG) of perpendicular magnetic anisotropy. Here we demonstrate large anomalous Hall resistance (RAHE) exceeding 8 Ω (ρAHE of 3.2 μΩ·cm) at 300 K and sustaining to 400 K in 35 BST/EuIG samples, surpassing the past record of 0.28 Ω (ρAHE of 0.14 μΩ·cm) at 300 K. The large RAHE is attributed to an atomically abrupt, Fe-rich interface between BST and EuIG. Importantly, the gate dependence of the AHE loops shows no sign change with varying chemical potential. This observation is supported by our first-principles calculations via applying a gradient Zeeman field plus a contact potential on BST. Our calculations further demonstrate that the AHE in this heterostructure is attributed to the intrinsic Berry curvature. Furthermore, for gate-biased 4 nm BST on EuIG, a pronounced topological Hall effect-like (THE-like) feature coexisting with AHE is observed at the negative top-gate voltage up to 15 K. Interface tuning with theoretical calculations has realized topologically distinct phenomena in tailored magnetic TI-based heterostructures.
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Affiliation(s)
- Wei-Jhih Zou
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Meng-Xin Guo
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Jyun-Fong Wong
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Zih-Ping Huang
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Jui-Min Chia
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wei-Nien Chen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Sheng-Xin Wang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Keng-Yung Lin
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Lawrence Boyu Young
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Yen-Hsun Glen Lin
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Mohammad Yahyavi
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chien-Ting Wu
- Materials Analysis Division, Taiwan Semiconductor Research Institute, National Applied Research Laboratories, Hsinchu 300091, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Shang-Fan Lee
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
| | - Minghwei Hong
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Jueinai Kwo
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
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6
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Takashiro T, Akiyama R, Kibirev IA, Matetskiy AV, Nakanishi R, Sato S, Fukasawa T, Sasaki T, Toyama H, Hiwatari KL, Zotov AV, Saranin AA, Hirahara T, Hasegawa S. Soft-Magnetic Skyrmions Induced by Surface-State Coupling in an Intrinsic Ferromagnetic Topological Insulator Sandwich Structure. NANO LETTERS 2022; 22:881-887. [PMID: 35084202 DOI: 10.1021/acs.nanolett.1c02952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A magnetic skyrmion induced on a ferromagnetic topological insulator (TI) is a real-space manifestation of the chiral spin texture in the momentum space and can be a carrier for information processing by manipulating it in tailored structures. Here, a sandwich structure containing two layers of a self-assembled ferromagnetic septuple-layer TI, Mn(Bi1-xSbx)2Te4 (MnBST), separated by quintuple layers of TI, (Bi1-xSbx)2Te3 (BST), is fabricated and skyrmions are observed through the topological Hall effect in an intrinsic magnetic topological insulator for the first time. The thickness of BST spacer layer is crucial in controlling the coupling between the gapped topological surface states in the two MnBST layers to stabilize the skyrmion formation. The homogeneous, highly ordered arrangement of the Mn atoms in the septuple-layer MnBST leads to a strong exchange interaction therein, which makes the skyrmions "soft magnetic". This would open an avenue toward a topologically robust rewritable magnetic memory.
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Affiliation(s)
- Takuya Takashiro
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Ryota Akiyama
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Ivan A Kibirev
- Institute of Automation and Control Processes, Vladivostok 690041, Russia
| | - Andrey V Matetskiy
- Institute of Automation and Control Processes, Vladivostok 690041, Russia
| | - Ryosuke Nakanishi
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Shunsuke Sato
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Takuro Fukasawa
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
| | - Taisuke Sasaki
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Haruko Toyama
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Kota L Hiwatari
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Andrey V Zotov
- Institute of Automation and Control Processes, Vladivostok 690041, Russia
| | | | - Toru Hirahara
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
| | - Shuji Hasegawa
- Department of Physics, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
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7
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Zhang X, Ambhire SC, Lu Q, Niu W, Cook J, Jiang JS, Hong D, Alahmed L, He L, Zhang R, Xu Y, Zhang SSL, Li P, Bian G. Giant Topological Hall Effect in van der Waals Heterostructures of CrTe 2/Bi 2Te 3. ACS NANO 2021; 15:15710-15719. [PMID: 34460216 DOI: 10.1021/acsnano.1c05519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Discoveries of the interfacial topological Hall effect (THE) provide an ideal platform for exploring the physics arising from the interplay between topology and magnetism. The interfacial topological Hall effect is closely related to the Dzyaloshinskii-Moriya interaction (DMI) at an interface and topological spin textures. However, it is difficult to achieve a sizable THE in heterostructures due to the stringent constraints on the constituents of THE heterostructures, such as strong spin-orbit coupling (SOC). Here, we report the observation of a giant THE signal of 1.39 μΩ·cm in the van der Waals heterostructures of CrTe2/Bi2Te3 fabricated by molecular beam epitaxy, a prototype of two-dimensional (2D) ferromagnet (FM)/topological insulator (TI). This large magnitude of THE is attributed to an optimized combination of 2D ferromagnetism in CrTe2, strong SOC in Bi2Te3, and an atomically sharp interface. Our work reveals CrTe2/Bi2Te3 as a convenient platform for achieving large interfacial THE in hybrid systems, which could be utilized to develop quantum science and high-density information storage devices.
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Affiliation(s)
- Xiaoqian Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Siddhesh C Ambhire
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Qiangsheng Lu
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Wei Niu
- New Energy Technology Engineering Laboratory of Jiangsu Provence & School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Jacob Cook
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Jidong Samuel Jiang
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deshun Hong
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Laith Alahmed
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Liang He
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Rong Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Yongbing Xu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
- York-Nanjing Joint Centre (YNJC) for spintronics and nano engineering, Department of Electronic Engineering, The University of York, York YO10 3DD, United Kingdom
| | - Steven S-L Zhang
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
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8
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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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9
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Zhao YF, Zhou LJ, Wang F, Wang G, Song T, Ovchinnikov D, Yi H, Mei R, Wang K, Chan MHW, Liu CX, Xu X, Chang CZ. Even-Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi 2Te 4 Thin Films. NANO LETTERS 2021; 21:7691-7698. [PMID: 34468149 DOI: 10.1021/acs.nanolett.1c02493] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recently, MnBi2Te4 has been demonstrated to be an intrinsic magnetic topological insulator and the quantum anomalous Hall (QAH) effect was observed in exfoliated MnBi2Te4 flakes. Here, we used molecular beam epitaxy (MBE) to grow MnBi2Te4 films with thickness down to 1 septuple layer (SL) and performed thickness-dependent transport measurements. We observed a nonsquare hysteresis loop in the antiferromagnetic state for films with thickness greater than 2 SL. The hysteresis loop can be separated into two AH components. We demonstrated that one AH component with the larger coercive field is from the dominant MnBi2Te4 phase, whereas the other AH component with the smaller coercive field is from the minor Mn-doped Bi2Te3 phase. The extracted AH component of the MnBi2Te4 phase shows a clear even-odd layer-dependent behavior. Our studies reveal insights on how to optimize the MBE growth conditions to improve the quality of MnBi2Te4 films.
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Affiliation(s)
- Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ling-Jie Zhou
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Fei Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Guang Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tiancheng Song
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Dmitry Ovchinnikov
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Hemian Yi
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ruobing Mei
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ke Wang
- Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chao-Xing Liu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
- Department of Material Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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