51
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Zhang C, Liu C, Zhang S, Zhou B, Guan C, Ma Y, Algaidi H, Zheng D, Li Y, He X, Zhang J, Li P, Hou Z, Yin G, Liu K, Peng Y, Zhang XX. Magnetic Skyrmions with Unconventional Helicity Polarization in a Van Der Waals Ferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204163. [PMID: 35975291 DOI: 10.1002/adma.202204163] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Skyrmion helicity, which defines the spin swirling direction, is a fundamental parameter that may be utilized to encode data bits in future memory devices. Generally, in centrosymmetric ferromagnets, dipole skyrmions with helicity of -π/2 and π/2 are degenerate in energy, leading to equal populations of both helicities. On the other hand, in chiral materials where the Dzyaloshinskii-Moriya interaction (DMI) prevails and the dipolar interaction is negligible, only a preferred helicity is selected by the type of DMI. However, whether there is a rigid boundary between these two regimes remains an open question. Herein, the observation of dipole skyrmions with unconventional helicity polarization in a van der Waals ferromagnet, Fe5- δ GeTe2 , is reported. Combining magnetometry, Lorentz transmission electron microscopy, electrical transport measurements, and micromagnetic simulations, the short-range superstructures in Fe5- δ GeTe2 resulting in a localized DMI contribution, which breaks the degeneracy of the opposite helicities and leads to the helicity polarization, is demonstrated. Therefore, the helicity feature in Fe5- δ GeTe2 is controlled by both the dipolar interaction and DMI that the former leads to Bloch-type skyrmions with helicity of ±π/2 whereas the latter breaks the helicity degeneracy. This work provides new insights into the skyrmion topology in van der Waals materials.
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Affiliation(s)
- Chenhui Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Bojian Zhou
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Chaoshuai Guan
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Yinchang Ma
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Hanin Algaidi
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xin He
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Peng Li
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Zhipeng Hou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Gen Yin
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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52
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Averyanov DV, Sokolov IS, Taldenkov AN, Parfenov OE, Tokmachev AM, Storchak VG. 2D magnetic phases of Eu on Ge(110). NANOSCALE 2022; 14:12377-12385. [PMID: 35972030 DOI: 10.1039/d2nr02777a] [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
2D magnetic materials are at the forefront of research on fundamentals of magnetism; they exhibit unconventional phases and properties controlled by external stimuli. 2D magnets offer a solution to the problem of miniaturization of spintronic devices. A technological target of materials science is to find suitable magnetic materials and scale their thickness down as much as possible, a single monolayer being a natural limit. However, magnetism does not halt at one monolayer - it may persist beyond this boundary, to sparse but regular lattices of magnetic atoms. Here, we report 2D magnetic phases of Eu on the Ge(110) surface. We synthesized two submonolayer structures Eu/Ge(110) employing molecular beam epitaxy. The phases, identified by electron diffraction, differ in the surface density of Eu atoms. At low temperature, they exhibit magnetic ordering with magnetic moments lying in-plane. Strong dependence of the effective magnetic transition temperature on weak magnetic fields points at the 2D nature of the observed magnetism. The results are set against those on the Eu/Si system. The study of Eu/Ge(110) magnets demonstrates that a variety of substrates of different structure and symmetry can host submonolayer 2D magnetic phases, suggesting the phenomenon to be rather general.
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Affiliation(s)
- Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
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53
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Guo Y, Zhao Y, Zhou S, Zhao J. Oxidation behavior of layered Fe nGeTe 2 ( n = 3, 4, 5) and Cr 2Ge 2Te 6 governed by interlayer coupling. NANOSCALE 2022; 14:11452-11460. [PMID: 35904500 DOI: 10.1039/d2nr02375j] [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
Layered magnetic materials have recently received tremendous attention due to an attractive combination of functional properties suitable for nanoelectronics and spintronic applications. Enhancing the air stability of the material is a prerequisite for long-term durability of devices. However, the oxidation mechanism of layered magnetic materials is yet to be revealed. Herein we explore the oxidation behavior of monolayer and multilayer FenGeTe2 (n = 3, 4, 5) and Cr2Ge2Te6 using first-principles calculations. The results show that these monolayer systems are prone to be oxidized in ambient air. With increasing thickness, however, multilayer FenGeTe2 exhibits distinct oxidation behavior from its monolayer counterparts, originating from its unexpected strong interlayer coupling characterized by wavefunction overlapping of adjacent Te atoms between FenGeTe2 layers. Moreover, O2 adsorption does not severely deteriorate the magnetism of layered FenGeTe2 and Cr2Ge2Te6. Given the fact that oxidation properties can be altered by interlayer coupling, our work opens a paradigm for obtaining oxidation-resistant layered materials.
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Affiliation(s)
- Yu Guo
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Yanyan Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Si Zhou
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
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54
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Albarakati S, Xie WQ, Tan C, Zheng G, Algarni M, Li J, Partridge J, Spencer MJS, Farrar L, Xiong Y, Tian M, Wang X, Zhao YJ, Wang L. Electric Control of Exchange Bias Effect in FePS 3-Fe 5GeTe 2 van der Waals Heterostructures. NANO LETTERS 2022; 22:6166-6172. [PMID: 35912475 DOI: 10.1021/acs.nanolett.2c01370] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Manipulating the exchange bias (EB) effect using an electronic gate is a significant goal in spintronics. The emergence of van der Waals (vdW) magnetic heterostructures has provided improved means to study interlayer magnetic coupling, but to date, these heterostructures have not exhibited electrical gate-controlled EB effects. Here, we report electrically controllable EB effects in a vdW heterostructure, FePS3-Fe5GeTe2. By applying a solid protonic gate, the EB effects were repeatably electrically tuned. The EB field reaches up to 23% of the coercivity and the blocking temperature ranges from 30 to 60 K under various gate-voltages. The proton intercalations not only tune the average magnetic exchange coupling but also change the antiferromagnetic configurations in the FePS3 layer. These result in a dramatic modulation of the total interface exchange coupling and the resultant EB effects. The study is a significant step toward vdW heterostructure-based magnetic logic for future low-energy electronics.
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Affiliation(s)
- Sultan Albarakati
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
- Physics Department, Faculty of Science and Arts, University of Jeddah, P.O. Box 80200, 21589Khulais, Saudi Arabia
| | - Wen-Qiang Xie
- Department of Physics, South China University of Technology, Guangzhou510640, China
| | - Cheng Tan
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Guolin Zheng
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - Meri Algarni
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Junbo Li
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - James Partridge
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Michelle J S Spencer
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Lawrence Farrar
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei, Anhui230031, China
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei, Anhui230601, China
| | - Xiaolin Wang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, New South Wales2500, Australia
- Institute for Superconducting & Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Yu-Jun Zhao
- Department of Physics, South China University of Technology, Guangzhou510640, China
| | - Lan Wang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, Victoria3001, Australia
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55
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Fujita R, Bassirian P, Li Z, Guo Y, Mawass MA, Kronast F, van der Laan G, Hesjedal T. Layer-Dependent Magnetic Domains in Atomically Thin Fe 5GeTe 2. ACS NANO 2022; 16:10545-10553. [PMID: 35802911 PMCID: PMC9331157 DOI: 10.1021/acsnano.2c01948] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Magnetic domain formation in two-dimensional (2D) materials gives perspectives into the fundamental origins of 2D magnetism and also motivates the development of advanced spintronics devices. However, the characterization of magnetic domains in atomically thin van der Waals (vdW) flakes remains challenging. Here, we employ X-ray photoemission electron microscopy (XPEEM) to perform layer-resolved imaging of the domain structures in the itinerant vdW ferromagnet Fe5GeTe2 which shows near room temperature bulk ferromagnetism and a weak perpendicular magnetic anisotropy (PMA). In the bulk limit, we observe the well-known labyrinth-type domains. Thinner flakes, on the other hand, are characterized by increasingly fragmented domains. While PMA is a characteristic property of Fe5GeTe2, we observe a spin-reorientation transition with the spins canting in-plane for flakes thinner than six layers. Notably, a bubble phase emerges in four-layer flakes. This thickness dependence, which clearly deviates from the single-domain behavior observed in other 2D magnetic materials, demonstrates the exciting prospect of stabilizing complex spin textures in 2D vdW magnets at relatively high temperatures.
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Affiliation(s)
- Ryuji Fujita
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
| | - Pedram Bassirian
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
- Max
Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Zhengxian Li
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Yanfeng Guo
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Mohamad A. Mawass
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Florian Kronast
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Gerrit van der Laan
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot, OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
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56
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Qian T, Emmanouilidou E, Hu C, Green JC, Mazin II, Ni N. Unconventional Pressure-Driven Metamagnetic Transitions in Topological van der Waals Magnets. NANO LETTERS 2022; 22:5523-5529. [PMID: 35731986 DOI: 10.1021/acs.nanolett.2c01680] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Activating metamagnetic transitions between ordered states in van der Waals magnets and devices bring great opportunities in spintronics. We show that external pressure, which enhances the interlayer hopping without introducing chemical disorders, triggers multiple metamagnetic transitions upon cooling in the topological van der Waals magnets Mn(Bi1-xSbx)4Te7, where the antiferromagnetic interlayer superexchange coupling competes with the ferromagnetic interlayer coupling mediated by the antisite Mn spins. The temperature-pressure phase diagrams reveal that while the ordering temperature from the paramagnetic to ordered states is almost pressure-independent, the metamagnetic transitions show nontrivial pressure and temperature dependence, even re-entrance. For these highly anisotropic magnets, we attribute the former to the ordering temperature being only weakly dependent on the intralayer parameters and the latter to the parametrically different pressure and temperature dependence of the two interlayer couplings. Our independent probing of these disparate magnetic interactions paves an avenue for efficient magnetic manipulations in van der Waals magnets.
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Affiliation(s)
- Tiema Qian
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Eve Emmanouilidou
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Chaowei Hu
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jazmine C Green
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Igor I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, United States
- Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia 22030, United States
| | - Ni Ni
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
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57
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Li JX, Li WQ, Hung SH, Chen PL, Yang YC, Chang TY, Chiu PW, Jeng HT, Liu CH. Electric control of valley polarization in monolayer WSe 2 using a van der Waals magnet. NATURE NANOTECHNOLOGY 2022; 17:721-728. [PMID: 35501377 DOI: 10.1038/s41565-022-01115-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Electrical manipulation of the valley degree of freedom in transition metal dichalcogenides is central to developing valleytronics. Towards this end, ferromagnetic contacts, such as Ga(Mn)As and permalloy, have been exploited to inject spin-polarized carriers into transition metal dichalcogenides to realize valley-dependent polarization. However, these materials require either a high external magnetic field or complicated epitaxial growth steps, limiting their practical applications. Here we report van der Waals heterostructures based on a monolayer WSe2 and an Fe3GeTe2/hexagonal boron nitride ferromagnetic tunnelling contact that under a bias voltage can effectively inject spin-polarized holes into WSe2, leading to a population imbalance between ±K valleys, as confirmed by density functional theory calculations and helicity-dependent electroluminescence measurements. Under an external magnetic field, we observe that the helicity of electroluminescence flips its sign and exhibits a hysteresis loop in agreement with the magnetic hysteresis loop obtained from reflective magnetic circular dichroism characterizations on Fe3GeTe2. Our results could address key challenges of valleytronics and prove promising for van der Waals magnets for magneto-optoelectronics applications.
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Affiliation(s)
- Jia-Xin Li
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Wei-Qing Li
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Sheng-Hsiung Hung
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
| | - Po-Liang Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Yueh-Chiang Yang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Tian-Yun Chang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.
- Institute of Physics, Academia Sinica, Taipei, Taiwan.
- Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan.
| | - Chang-Hua Liu
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan.
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
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58
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Li Z, Tang M, Huang J, Qin F, Ao L, Shen Z, Zhang C, Chen P, Bi X, Qiu C, Yu Z, Zhai K, Ideue T, Wang L, Liu Z, Tian Y, Iwasa Y, Yuan H. Magnetic Anisotropy Control with Curie Temperature above 400 K in a van der Waals Ferromagnet for Spintronic Device. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201209. [PMID: 35448916 DOI: 10.1002/adma.202201209] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/07/2022] [Indexed: 06/14/2023]
Abstract
The technological appeal of van der Waals ferromagnetic materials is the ability to control magnetism under external fields with desired thickness toward novel spintronic applications. For practically useful devices, ferromagnetism above room temperature or tunable magnetic anisotropy is highly demanded but remains challenging. To date, only a few layered materials exhibit unambiguous ferromagnetic ordering at room temperature via gating techniques or interface engineering. Here, it is demonstrated that the magnetic anisotropy control and dramatic modulation of Curie temperature (Tc ) up to 400 K are realized in layered Fe5 GeTe2 via the high-pressure diamond-anvil-cell technique. Magnetic phases manifesting with in-plane anisotropic, out-of-plane anisotropic and nearly isotropic magnetic states can be tuned in a controllable way, depicted by the phase diagram with a maximum Tc up to 360 K. Remarkably, the Tc can be gradually enhanced to above 400 K owing to the Fermi surface evolution during a pressure loading-deloading process. Such an observation sheds light on the understanding and control of emergent magnetic states in practical spintronic applications.
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Affiliation(s)
- Zeya Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Ming Tang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
- School of Physics, Nanjing University, Nanjing, 210000, China
| | - Junwei Huang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Feng Qin
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Lingyi Ao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Zhiwei Shen
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Caorong Zhang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
- School of Physics, Nanjing University, Nanjing, 210000, China
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Xiangyu Bi
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Caiyu Qiu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Zhipeng Yu
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Kun Zhai
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Toshiya Ideue
- Quantum Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Lin Wang
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Zhongyuan Liu
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Yongjun Tian
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Yoshihiro Iwasa
- Quantum Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Hirosawa 2-1, Wako, 351-0198, Japan
| | - Hongtao Yuan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
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59
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Husremović S, Groschner CK, Inzani K, Craig IM, Bustillo KC, Ercius P, Kazmierczak NP, Syndikus J, Van Winkle M, Aloni S, Taniguchi T, Watanabe K, Griffin SM, Bediako DK. Hard Ferromagnetism Down to the Thinnest Limit of Iron-Intercalated Tantalum Disulfide. J Am Chem Soc 2022; 144:12167-12176. [PMID: 35732002 DOI: 10.1021/jacs.2c02885] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two-dimensional (2D) magnetic crystals hold promise for miniaturized and ultralow power electronic devices that exploit spin manipulation. In these materials, large, controllable magnetocrystalline anisotropy (MCA) is a prerequisite for the stabilization and manipulation of long-range magnetic order. In known 2D magnetic crystals, relatively weak MCA typically results in soft ferromagnetism. Here, we demonstrate that ferromagnetic order persists down to the thinnest limit of FexTaS2 (Fe-intercalated bilayer 2H-TaS2) with giant coercivities up to 3 T. We prepare Fe-intercalated TaS2 by chemical intercalation of van der Waals-layered 2H-TaS2 crystals and perform variable-temperature transport, transmission electron microscopy, and confocal Raman spectroscopy measurements to shed new light on the coupled effects of dimensionality, degree of intercalation, and intercalant order/disorder on the hard ferromagnetic behavior of FexTaS2. More generally, we show that chemical intercalation gives access to a rich synthetic parameter space for low-dimensional magnets, in which magnetic properties can be tailored by the choice of the host material and intercalant identity/amount, in addition to the manifold distinctive degrees of freedom available in atomically thin, van der Waals crystals.
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Affiliation(s)
- Samra Husremović
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Catherine K Groschner
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Katherine Inzani
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Isaac M Craig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Karen C Bustillo
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Nathanael P Kazmierczak
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jacob Syndikus
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Madeline Van Winkle
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Shaul Aloni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Takashi Taniguchi
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Sinéad M Griffin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - D Kwabena Bediako
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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60
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Ershadrad S, Ghosh S, Wang D, Kvashnin Y, Sanyal B. Unusual Magnetic Features in Two-Dimensional Fe 5GeTe 2 Induced by Structural Reconstructions. J Phys Chem Lett 2022; 13:4877-4883. [PMID: 35617439 PMCID: PMC9189922 DOI: 10.1021/acs.jpclett.2c00692] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Recent experiments on Fe5GeTe2 suggested the presence of a symmetry breaking of its conventional crystal structure. Here, using density functional theory calculations, we elucidate that the stabilization of the (√3 × √3)R30° supercell structure is caused by the swapping of Fe atoms occurring in the monolayer limit. The swapping to the vicinity of Te atoms is facilitated by the spontaneous occurrence of Fe vacancy and its low diffusion barrier. Our calculated magnetic exchange parameters show the simultaneous presence of ferromagnetic and antiferromagnetic exchange among a particular type of Fe atom. The Fe sublattice projected magnetization obtained from Monte Carlo simulations clearly demonstrates an exotic temperature-dependent behavior of this Fe type along with a large canting angle at T = 0 K, indicating the presence of a complex noncollinear magnetic order. We propose that the low-temperature crystal structure results from the swapping between two sublattices of Fe, giving rise to peculiar magnetization obtained in experiments.
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61
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Verchenko VY, Stepanova AV, Bogach AV, Mironov AV, Shevelkov AV. Fe-Rich Ferromagnetic Cleavable Van der Waals Telluride Fe 5AsTe 2. Inorg Chem 2022; 61:9224-9230. [PMID: 35658443 DOI: 10.1021/acs.inorgchem.2c00800] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride Fe5AsTe2 can be synthesized by the high-temperature reaction of elements. In the crystal structure, Fe-rich structural layers with the composition of Fe4.58(4)AsTe2 are separated by the van der Waals gaps with no atoms in the interstitial region. Crystal growth employing chemical vapor transport reactions yields bulk cleavable crystals, which exhibit weak inherent ferromagnetism below the Curie temperature of TC = 48 K. In the ordered state, the magnetization shows a dual-slope behavior in low magnetic fields, indicating the compensated or canted nature of magnetism. Magnetic susceptibility and magnetization measurements reveal perpendicular magnetic anisotropy. The large Rhodes-Wohlfarth ratio of 4.6 indicates the itinerant nature of ferromagnetism in Fe5AsTe2.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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62
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Verchenko VY, Kanibolotskiy AV, Bogach AV, Znamenkov KO, Shevelkov AV. Ferromagnetic correlations in the layered van der Waals sulfide FeAl 2S 4. Dalton Trans 2022; 51:8454-8460. [PMID: 35593508 DOI: 10.1039/d2dt00671e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transition metal-based layered compounds with van der Waals gaps between the adjacent layers are a source of two-dimensional (2D) nanomaterials with nontrivial transport and magnetic properties. 2D ferromagnets, both metals and semiconductors, can be leveraged to produce spin-polarized current in spintronic devices with tailored functionalities. Here, we report on the synthesis, crystal growth, crystal and electronic structure, and magnetic properties of the Fe-based FeAl2S4 layered sulfide. In the crystal structure, Fe and Al atoms mix on octahedral and tetrahedral sites between hexagonal layers of S atoms, which are terminated by the van der Waals gaps. Band structure calculations reveal strong electronic correlations within the semiconducting ground state, which induce ferromagnetism with the magnetic moment of 0.12μB per formula unit for a Hubbard interaction U = 5 eV and Hund's rule coupling J = 0.8 eV. Crystal growth employing chemical vapor transport reactions results in bulk cleavable crystals, which show paramagnetic Curie-Weiss behavior at high temperatures with the Fe2+ magnetic centers. At low temperatures, an anomaly is observed on the magnetic susceptibility curve, below which the magnetization shows ferromagnetic hysteresis, indicating the presence of ferromagnetic correlations in FeAl2S4.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia. .,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | | | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
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63
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Chen X, Shao YT, Chen R, Susarla S, Hogan T, He Y, Zhang H, Wang S, Yao J, Ercius P, Muller DA, Ramesh R, Birgeneau RJ. Pervasive beyond Room-Temperature Ferromagnetism in a Doped van der Waals Magnet. PHYSICAL REVIEW LETTERS 2022; 128:217203. [PMID: 35687434 DOI: 10.1103/physrevlett.128.217203] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
The existence of long-range magnetic order in low-dimensional magnetic systems, such as the quasi-two-dimensional van der Waals (vdW) magnets, has attracted intensive studies of new physical phenomena. The vdW Fe_{N}GeTe_{2} (N=3, 4, 5; FGT) family is exceptional, owing to its vast tunability of magnetic properties. In particular, a ferromagnetic ordering temperature (T_{C}) above room temperature at N=5 (F5GT) is observed. Here, our study shows that, by nickel (Ni) substitution of iron in F5GT, a record high T_{C}=478(6) K is achieved. Importantly, pervasive, beyond room-temperature ferromagnetism exists in almost the entire doping range of the phase diagram of Ni-F5GT. We argue that this striking observation in Ni-F5GT can be possibly due to several contributing factors, including increased 3D magnetic couplings due to the structural alterations.
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Affiliation(s)
- Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Rui Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Tom Hogan
- Quantum Design, Inc., San Diego, California 92121, USA
| | - Yu He
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut, 06511, USA
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Siqi Wang
- NSF Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA
| | - Jie Yao
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Peter Ercius
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
| | - Ramamoorthy Ramesh
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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64
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Wang QH, Bedoya-Pinto A, Blei M, Dismukes AH, Hamo A, Jenkins S, Koperski M, Liu Y, Sun QC, Telford EJ, Kim HH, Augustin M, Vool U, Yin JX, Li LH, Falin A, Dean CR, Casanova F, Evans RFL, Chshiev M, Mishchenko A, Petrovic C, He R, Zhao L, Tsen AW, Gerardot BD, Brotons-Gisbert M, Guguchia Z, Roy X, Tongay S, Wang Z, Hasan MZ, Wrachtrup J, Yacoby A, Fert A, Parkin S, Novoselov KS, Dai P, Balicas L, Santos EJG. The Magnetic Genome of Two-Dimensional van der Waals Materials. ACS NANO 2022; 16:6960-7079. [PMID: 35442017 PMCID: PMC9134533 DOI: 10.1021/acsnano.1c09150] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/23/2022] [Indexed: 05/23/2023]
Abstract
Magnetism in two-dimensional (2D) van der Waals (vdW) materials has recently emerged as one of the most promising areas in condensed matter research, with many exciting emerging properties and significant potential for applications ranging from topological magnonics to low-power spintronics, quantum computing, and optical communications. In the brief time after their discovery, 2D magnets have blossomed into a rich area for investigation, where fundamental concepts in magnetism are challenged by the behavior of spins that can develop at the single layer limit. However, much effort is still needed in multiple fronts before 2D magnets can be routinely used for practical implementations. In this comprehensive review, prominent authors with expertise in complementary fields of 2D magnetism (i.e., synthesis, device engineering, magneto-optics, imaging, transport, mechanics, spin excitations, and theory and simulations) have joined together to provide a genome of current knowledge and a guideline for future developments in 2D magnetic materials research.
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Affiliation(s)
- Qing Hua Wang
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Amilcar Bedoya-Pinto
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
- Instituto
de Ciencia Molecular (ICMol), Universitat
de València, 46980 Paterna, Spain
| | - Mark Blei
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Avalon H. Dismukes
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Assaf Hamo
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sarah Jenkins
- Twist
Group,
Faculty of Physics, University of Duisburg-Essen, Campus Duisburg, 47057 Duisburg, Germany
| | - Maciej Koperski
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Yu Liu
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Qi-Chao Sun
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
| | - Evan J. Telford
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Hyun Ho Kim
- School
of Materials Science and Engineering, Department of Energy Engineering
Convergence, Kumoh National Institute of
Technology, Gumi 39177, Korea
| | - Mathias Augustin
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Uri Vool
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John Harvard
Distinguished Science Fellows Program, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Jia-Xin Yin
- Laboratory
for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Lu Hua Li
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Alexey Falin
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Cory R. Dean
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Fèlix Casanova
- CIC nanoGUNE
BRTA, 20018 Donostia - San Sebastián, Basque
Country, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Richard F. L. Evans
- Department
of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Mairbek Chshiev
- Université
Grenoble Alpes, CEA, CNRS, Spintec, 38000 Grenoble, France
- Institut
Universitaire de France, 75231 Paris, France
| | - Artem Mishchenko
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Cedomir Petrovic
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rui He
- Department
of Electrical and Computer Engineering, Texas Tech University, 910 Boston Avenue, Lubbock, Texas 79409, United
States
| | - Liuyan Zhao
- Department
of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109, United States
| | - Adam W. Tsen
- Institute
for Quantum Computing and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Brian D. Gerardot
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Mauro Brotons-Gisbert
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Zurab Guguchia
- Laboratory
for Muon Spin Spectroscopy, Paul Scherrer
Institute, CH-5232 Villigen PSI, Switzerland
| | - Xavier Roy
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sefaattin Tongay
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Ziwei Wang
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - M. Zahid Hasan
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Princeton
Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Joerg Wrachtrup
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
- Max Planck
Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Amir Yacoby
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John A.
Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Albert Fert
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Department
of Materials Physics UPV/EHU, 20018 Donostia - San Sebastián, Basque Country, Spain
| | - Stuart Parkin
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
| | - Kostya S. Novoselov
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Pengcheng Dai
- Department
of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Luis Balicas
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Elton J. G. Santos
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Higgs Centre
for Theoretical Physics, The University
of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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65
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Zhang H, Raftrey D, Chan YT, Shao YT, Chen R, Chen X, Huang X, Reichanadter JT, Dong K, Susarla S, Caretta L, Chen Z, Yao J, Fischer P, Neaton JB, Wu W, Muller DA, Birgeneau RJ, Ramesh R. Room-temperature skyrmion lattice in a layered magnet (Fe 0.5Co 0.5) 5GeTe 2. SCIENCE ADVANCES 2022; 8:eabm7103. [PMID: 35319983 PMCID: PMC8942374 DOI: 10.1126/sciadv.abm7103] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/28/2022] [Indexed: 05/26/2023]
Abstract
Novel magnetic ground states have been stabilized in two-dimensional (2D) magnets such as skyrmions, with the potential next-generation information technology. Here, we report the experimental observation of a Néel-type skyrmion lattice at room temperature in a single-phase, layered 2D magnet, specifically a 50% Co-doped Fe5GeTe2 (FCGT) system. The thickness-dependent magnetic domain size follows Kittel's law. The static spin textures and spin dynamics in FCGT nanoflakes were studied by Lorentz electron microscopy, variable-temperature magnetic force microscopy, micromagnetic simulations, and magnetotransport measurements. Current-induced skyrmion lattice motion was observed at room temperature, with a threshold current density, jth = 1 × 106 A/cm2. This discovery of a skyrmion lattice at room temperature in a noncentrosymmetric material opens the way for layered device applications and provides an ideal platform for studies of topological and quantum effects in 2D.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - David Raftrey
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Physics Department, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Ying-Ting Chan
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Jonathan T. Reichanadter
- Department of Electrical Engineering, University of California, Berkeley, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Kaichen Dong
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sandhya Susarla
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Zhen Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Physics Department, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jeffrey B. Neaton
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
- Kavli Energy Nanosciences Institute at Berkeley, Berkeley, CA, USA
| | - Weida Wu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - David A. Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA
| | - Robert J. Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
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66
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Lin H, Luo X, Liu L, Wang D, Zhao X, Wang Z, Xue X, Zhang F, Xing G. All-Electrical Control of Compact SOT-MRAM: Toward Highly Efficient and Reliable Non-Volatile In-Memory Computing. MICROMACHINES 2022; 13:mi13020319. [PMID: 35208443 PMCID: PMC8876745 DOI: 10.3390/mi13020319] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 02/01/2023]
Abstract
Two-dimensional van der Waals (2D vdW) ferromagnets possess outstanding scalability, controllable ferromagnetism, and out-of-plane anisotropy, enabling the compact spintronics-based non-volatile in-memory computing (nv-IMC) that promises to tackle the memory wall bottleneck issue. Here, by employing the intriguing room-temperature ferromagnetic characteristics of emerging 2D Fe3GeTe2 with the dissimilar electronic structure of the two spin-conducting channels, we report on a new type of non-volatile spin-orbit torque (SOT) magnetic tunnel junction (MTJ) device based on Fe3GeTe2/MgO/Fe3GeTe2 heterostructure, which demonstrates the uni-polar and high-speed field-free magnetization switching by adjusting the ratio of field-like torque to damping-like torque coefficient in the free layer. Compared to the conventional 2T1M structure, the developed 3-transistor-2-MTJ (3T2M) cell is implemented with the complementary data storage feature and the enhanced sensing margin of 201.4% (from 271.7 mV to 547.2 mV) and 276% (from 188.2 mV to 520 mV) for reading “1” and “0”, respectively. Moreover, superior to the traditional CoFeB-based MTJ memory cell counterpart, the 3T2M crossbar array architecture can be executed for AND/NAND, OR/NOR Boolean logic operation with a fast latency of 24 ps and ultra-low power consumption of 2.47 fJ/bit. Such device to architecture design with elaborated micro-magnetic and circuit-level simulation results shows great potential for realizing high-performance 2D material-based compact SOT magnetic random-access memory, facilitating new applications of highly reliable and energy-efficient nv-IMC.
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Affiliation(s)
- Huai Lin
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xi Luo
- Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081, China;
| | - Long Liu
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Di Wang
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xuefeng Zhao
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Ziwei Wang
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyong Xue
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 201203, China;
| | - Feng Zhang
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
| | - Guozhong Xing
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China; (H.L.); (L.L.); (D.W.); (X.Z.); (Z.W.); (F.Z.)
- University of the Chinese Academy of Sciences, Beijing 100049, China
- Correspondence:
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67
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Ko W, Gai Z, Puretzky AA, Liang L, Berlijn T, Hachtel JA, Xiao K, Ganesh P, Yoon M, Li AP. Understanding Heterogeneities in Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2106909. [PMID: 35170112 DOI: 10.1002/adma.202106909] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Quantum materials are usually heterogeneous, with structural defects, impurities, surfaces, edges, interfaces, and disorder. These heterogeneities are sometimes viewed as liabilities within conventional systems; however, their electronic and magnetic structures often define and affect the quantum phenomena such as coherence, interaction, entanglement, and topological effects in the host system. Therefore, a critical need is to understand the roles of heterogeneities in order to endow materials with new quantum functions for energy and quantum information science applications. In this article, several representative examples are reviewed on the recent progress in connecting the heterogeneities to the quantum behaviors of real materials. Specifically, three intertwined topic areas are assessed: i) Reveal the structural, electronic, magnetic, vibrational, and optical degrees of freedom of heterogeneities. ii) Understand the effect of heterogeneities on the behaviors of quantum states in host material systems. iii) Control heterogeneities for new quantum functions. This progress is achieved by establishing the atomistic-level structure-property relationships associated with heterogeneities in quantum materials. The understanding of the interactions between electronic, magnetic, photonic, and vibrational states of heterogeneities enables the design of new quantum materials, including topological matter and quantum light emitters based on heterogenous 2D materials.
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Affiliation(s)
- Wonhee Ko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Zheng Gai
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Tom Berlijn
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Mina Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - An-Ping Li
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
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68
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Zhang S, Wu H, Yang L, Zhang G, Xie Y, Zhang L, Zhang W, Chang H. Two-dimensional magnetic atomic crystals. MATERIALS HORIZONS 2022; 9:559-576. [PMID: 34779810 DOI: 10.1039/d1mh01155c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) magnetic crystals show many fascinating physical properties and have potential device applications in many fields. In this paper, the preparation, physical properties and device applications of 2D magnetic atomic crystals are reviewed. First, three preparation methods are presented, including chemical vapor deposition (CVD) molecular beam epitaxy (MBE) and single-crystal exfoliation. Second, physical properties of 2D magnetic atomic crystals, including ferromagnetism, antiferromagnetism, magnetic regulation and anomalous Hall effect are presented. Third, the application of 2D magnetic atomic crystals in heterojunctions reluctance and other aspects are briefly introduced. Finally, the future development direction and possible challenges of 2D magnetic atomic crystals are briefly addressed.
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Affiliation(s)
- Shanfei Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Hao Wu
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Li Yang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Gaojie Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Yuanmiao Xie
- School of Microelectronics and Materials Engineering and School of Science, Guangxi University of Science and Technology, Liuzhou, China
| | - Liang Zhang
- School of Microelectronics and Materials Engineering and School of Science, Guangxi University of Science and Technology, Liuzhou, China
| | - Wenfeng Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Haixin Chang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
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69
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Peng B, Chen Z, Li Y, Liu Z, Liang D, Deng L. Multiwavelength magnetic coding of helical luminescence in ferromagnetic 2D layered CrI 3. iScience 2022; 25:103623. [PMID: 35005559 PMCID: PMC8718829 DOI: 10.1016/j.isci.2021.103623] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/15/2021] [Accepted: 12/10/2021] [Indexed: 11/01/2022] Open
Abstract
Two-dimensional (2D) van der Waals (vdW) ferromagnets have opened new avenues for manipulating spin at the limits of single or few atomic layers, and for creating unique magneto-exciton devices through the coupling of ferromagnetic (FM) orders and excitons. However, 2D vdW ferromagnets explored so far have rarely possessed exciton behaviors; to date, FM CrI3 have been revealed to show ligand-field photoluminescence correlated with FM ordering, but typically with a broad emission peak. Here, we report a straightforward approach to realize strong coupling of narrow helical emission and FM orders in CrI3 through microsphere cavity. The resonant whispering-gallery modes (WGM) of SiO2 microspheres cause strong oscillation helical emissions with a full width at half-maximum (FWHM) of ∼5 nm under continuous wave excitation. Reversible magnetic coding of helical luminescence is realized in the range of 950-1100 nm. This work enables numerous opportunities for creating magnetic encoding lasing for photonic integrated chips.
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Affiliation(s)
- Bo Peng
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zhiyong Chen
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yue Li
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zhen Liu
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Difei Liang
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Longjiang Deng
- National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.,State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China
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70
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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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71
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Wang S, Xu J, Li W, Sun S, Gao S, Hou Y. Magnetic Nanostructures: Rational Design and Fabrication Strategies toward Diverse Applications. Chem Rev 2022; 122:5411-5475. [PMID: 35014799 DOI: 10.1021/acs.chemrev.1c00370] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In recent years, the continuous development of magnetic nanostructures (MNSs) has tremendously promoted both fundamental scientific research and technological applications. Different from the bulk magnet, the systematic engineering on MNSs has brought a great breakthrough in some emerging fields such as the construction of MNSs, the magnetism exploration of multidimensional MNSs, and their potential translational applications. In this review, we give a detailed description of the synthetic strategies of MNSs based on the fundamental features and application potential of MNSs and discuss the recent progress of MNSs in the fields of nanomedicines, advanced nanobiotechnology, catalysis, and electromagnetic wave adsorption (EMWA), aiming to provide guidance for fabrication strategies of MNSs toward diverse applications.
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Affiliation(s)
- Shuren Wang
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Beijing Innovation Centre for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China
| | - Junjie Xu
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Beijing Innovation Centre for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China
| | - Wei Li
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Beijing Innovation Centre for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China
| | - Shengnan Sun
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Beijing Innovation Centre for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China
| | - Song Gao
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Institute of Spin-X Science and Technology, South China University of Technology, Guangzhou 511442, China
| | - Yanglong Hou
- Beijing Key Laboratory of Magnetoelectric Materials and Devices, School of Materials Science and Engineering, Beijing Innovation Centre for Engineering Science and Advanced Technology, Peking University, Beijing 100871, China
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72
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Rana B, Mondal AK, Bandyopadhyay S, Barman A. Applications of nanomagnets as dynamical systems: II. NANOTECHNOLOGY 2021; 33:082002. [PMID: 34644699 DOI: 10.1088/1361-6528/ac2f59] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
In Part I of this topical review, we discussed dynamical phenomena in nanomagnets, focusing primarily on magnetization reversal with an eye to digital applications. In this part, we address mostly wave-like phenomena in nanomagnets, with emphasis on spin waves in myriad nanomagnetic systems and methods of controlling magnetization dynamics in nanomagnet arrays which may have analog applications. We conclude with a discussion of some interesting spintronic phenomena that undergird the rich physics exhibited by nanomagnet assemblies.
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Affiliation(s)
- Bivas Rana
- Institute of Spintronics and Quantum Information, Faculty of Physics, Adam Mickiewicz University in Poznań, Uniwersytetu Poznanskiego 2, Poznań 61-614, Poland
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Amrit Kumar Mondal
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 106, India
| | - Supriyo Bandyopadhyay
- Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA, 23284, United States of America
| | - Anjan Barman
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 106, India
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73
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Hu L, Zhou J, Hou Z, Su W, Yang B, Li L, Yan M. Polymer-buried van der Waals magnets for promising wearable room-temperature spintronics. MATERIALS HORIZONS 2021; 8:3306-3314. [PMID: 34751291 DOI: 10.1039/d1mh01439k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The demand for high-performance spintronic devices has boosted intense research on the manipulation of magnetism in van der Waals (vdW) magnets. Despite great efforts, robust ferromagnetic transitions above room temperature still face significant hurdles. Strain engineering can reversibly regulate magnetic exchange, but the degree of regulation is still impractical for most magnetic applications. Hereby we employ a large-strain transferrer to produce tunable strains of up to 4.7%, which induces authentic room-temperature ferromagnetism in large-area Fe3GeTe2 nanoflakes with 20-fold improvement in magnetization. The record increment of the Curie temperature (TC) of well above 400 K originates from the strain-enhanced magnetic anisotropy and excellent magnetoelastic coupling. The correlation between the emerging ferromagnetism and Raman spectral evolution is also established, which complements well the TC phase diagram in a large-strain region. In addition, an unusual exchange bias effect with a vertical magnetization shift is tracked for the first time upon bending, which reveals the hidden competition between antiferromagnetic and ferromagnetic coupling. The reversible strain manipulation of single-domain ferromagnetic order in a single nanoflake further opens up a route to develop low-power wearable spintronic devices. The findings here provide vast opportunities to exploit the possibility of practical applications of more vdW magnets.
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Affiliation(s)
- Liang Hu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
- State Key Lab of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Jian Zhou
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
| | - Zhipeng Hou
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Weitao Su
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
| | - Bingzhang Yang
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
| | - Lingwei Li
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
| | - Mi Yan
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
- State Key Lab of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
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74
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Zhao Y, Liu H, Gao J, Zhao J. Transition of CrI 2 from a two-dimensional network to one-dimensional chain at the monolayer limit. Phys Chem Chem Phys 2021; 23:25291-25297. [PMID: 34735565 DOI: 10.1039/d1cp03789g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Two-dimensional (2D) magnets show promising applications in spintronic devices and appeal increasing attention. CrI2, a counterpart of CrI3, is a magnetic van der Waals crystal. However, the structure of CrI2 at the monolayer limit is not well studied. Here, based on the density functional theory, we revealed the relationship between different phases of CrI2 monolayer and proposed a novel and stable chain structure. The one-dimensional (1D) CrI2 chain is a ferromagnetic semiconductor with robust electronic properties against twisting and tensile strain. Interestingly, the CrI2 chain exhibits superelasticity with a failure strain as large as 39%. In addition, both the magnetic moments on Cr atoms and the exchange energy increase with an increase in the tensile strain. Our results push magnetic ordering from 2D to 1D, which shows possible application prospects in magnetoelectric and spintronic devices.
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Affiliation(s)
- Yuanyuan Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Hongsheng Liu
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Junfeng Gao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
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75
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Chua R, Zhou J, Yu X, Yu W, Gou J, Zhu R, Zhang L, Liu M, Breese MBH, Chen W, Loh KP, Feng YP, Yang M, Huang YL, Wee ATS. Room Temperature Ferromagnetism of Monolayer Chromium Telluride with Perpendicular Magnetic Anisotropy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103360. [PMID: 34477241 DOI: 10.1002/adma.202103360] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/18/2021] [Indexed: 06/13/2023]
Abstract
The realization of long-range magnetic ordering in 2D systems can potentially revolutionize next-generation information technology. Here, the successful fabrication of crystalline Cr3 Te4 monolayers with room temperature (RT) ferromagnetism is reported. Using molecular beam epitaxy, the growth of 2D Cr3 Te4 films with monolayer thickness is demonstrated at low substrate temperatures (≈100 °C), compatible with Si complementary metal oxide semiconductor technology. X-ray magnetic circular dichroism measurements reveal a Curie temperature (Tc ) of v344 K for the Cr3 Te4 monolayer with an out-of-plane magnetic easy axis, which decreases to v240 K for the thicker film (≈7 nm) with an in-plane easy axis. The enhancement of ferromagnetic coupling and the magnetic anisotropy transition is ascribed to interfacial effects, in particular the orbital overlap at the monolayer Cr3 Te4 /graphite interface, supported by density-functional theory calculations. This work sheds light on the low-temperature scalable growth of 2D nonlayered materials with RT ferromagnetism for new magnetic and spintronic devices.
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Affiliation(s)
- Rebekah Chua
- NUS Graduate School for Integrative Sciences & Engineering (NGS), University Hall, Tan Chin Tuan Wing, 21 Lower Kent Ridge, Singapore, 119077, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Jun Zhou
- Institute of Materials Research & Engineering, A*STAR (Agency for Science Technology and Research), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Wei Yu
- Department of Chemistry, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Jian Gou
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Rui Zhu
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Lei Zhang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Meizhuang Liu
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Mark B H Breese
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Wei Chen
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
- Department of Chemistry, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou, 350207, China
| | - Kian Ping Loh
- NUS Graduate School for Integrative Sciences & Engineering (NGS), University Hall, Tan Chin Tuan Wing, 21 Lower Kent Ridge, Singapore, 119077, Singapore
- Department of Chemistry, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Yuan Ping Feng
- NUS Graduate School for Integrative Sciences & Engineering (NGS), University Hall, Tan Chin Tuan Wing, 21 Lower Kent Ridge, Singapore, 119077, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - Ming Yang
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Yu Li Huang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou, 350207, China
| | - Andrew T S Wee
- NUS Graduate School for Integrative Sciences & Engineering (NGS), University Hall, Tan Chin Tuan Wing, 21 Lower Kent Ridge, Singapore, 119077, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
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76
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Kim D, Lee C, Jang BG, Kim K, Shim JH. Drastic change of magnetic anisotropy in Fe 3GeTe 2 and Fe 4GeTe 2 monolayers under electric field studied by density functional theory. Sci Rep 2021; 11:17567. [PMID: 34475450 PMCID: PMC8413389 DOI: 10.1038/s41598-021-96639-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/02/2021] [Indexed: 11/09/2022] Open
Abstract
Magnetic anisotropy energy (MAE) is one of the most important properties in two-dimensional magnetism since the magnetization in two dimension is vulnerable to the spin rotational fluctuations. Using density functional theory calculation, we show that perpendicular electric field dramatically enhances the in-plane and out-of-plane magnetic anisotropies in Fe3GeTe2 and Fe4GeTe2 monolayers, respectively, allowing the change of easy axis in both systems. The changes of the MAE under the electric field are understood as the result of charge redistribution inside the layer, which is available due to the three-dimensional (3D) network of Fe atoms in the monolayers. As a result, we suggest that due to the unique structure of FenGeTe2 compounds composed by peculiar 3D networks of metal atoms, the MAE can be dramatically changed by the external perpendicular electric field.
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Affiliation(s)
- Dongwook Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Changhoon Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea.,Max Planck POSTECH Center for Complex Phase of Materials, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Bo Gyu Jang
- Korea Institute for Advanced Study (KIAS), Seoul, 02455, Korea
| | - Kyoo Kim
- Korea Atomic Energy Research Institute (KAERI), Daejeon, 37673, Korea
| | - Ji Hoon Shim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea. .,Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea.
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77
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Zhang C, Zhang J, Liu C, Zhang S, Yuan Y, Li P, Wen Y, Jiang Z, Zhou B, Lei Y, Zheng D, Song C, Hou Z, Mi W, Schwingenschlögl U, Manchon A, Qiu ZQ, Alshareef HN, Peng Y, Zhang XX. Chiral Helimagnetism and One-Dimensional Magnetic Solitons in a Cr-Intercalated Transition Metal Dichalcogenide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101131. [PMID: 34302387 DOI: 10.1002/adma.202101131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/25/2021] [Indexed: 06/13/2023]
Abstract
Chiral magnets endowed with topological spin textures are expected to have promising applications in next-generation magnetic memories. In contrast to the well-studied 2D or 3D magnetic skyrmions, the authors report the discovery of 1D nontrivial magnetic solitons in a transition metal dichalcogenide 2H-TaS2 via precise intercalation of Cr elements. In the synthetic Cr1/3 TaS2 (CTS) single crystal, the coupling of the strong spin-orbit interaction from TaS2 and the chiral arrangement of the magnetic Cr ions evoke a robust Dzyaloshinskii-Moriya interaction. A magnetic helix having a short spatial period of ≈25 nm is observed in CTS via Lorentz transmission electron microscopy. In a magnetic field perpendicular to the helical axis, the helical spin structure transforms into a chiral soliton lattice (CSL) with the spin structure evolution being consistent with the chiral sine-Gordon theory, which opens promising perspectives for the application of CSL to fast-speed nonvolatile magnetic memories. This work introduces a new paradigm to soliton physics and provides an effective strategy for seeking novel 2D magnets.
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Affiliation(s)
- Chenhui Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Junwei Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, Gansu Province, 730000, China
| | - Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Ye Yuan
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Peng Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Wen
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Ze Jiang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, Gansu Province, 730000, China
| | - Bojian Zhou
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, Gansu Province, 730000, China
| | - Yongjiu Lei
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Chengkun Song
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, Gansu Province, 730000, China
| | - Zhipeng Hou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, Guangdong Province, 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, Guangdong Province, 510006, China
| | - Wenbo Mi
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin, Tianjin Municipality, 300354, China
| | - Udo Schwingenschlögl
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | | | - Zi Qiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Husam N Alshareef
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yong Peng
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, Gansu Province, 730000, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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78
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Yao Y, Zhan X, Sendeku MG, Yu P, Dajan FT, Zhu C, Li N, Wang J, Wang F, Wang Z, He J. Recent progress on emergent two-dimensional magnets and heterostructures. NANOTECHNOLOGY 2021; 32:472001. [PMID: 34315143 DOI: 10.1088/1361-6528/ac17fd] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Intrinsic two-dimensional (2D) magnetic materials own strong long-range magnetism while their characteristics of the ultrathin thickness and smooth surface provide an ideal platform for manipulating the magnetic properties at 2D limit. This makes them to be potential candidates in various spintronic applications compared to their corresponding bulk counterparts. The discovery of magnetic ordering in 2D CrI3and Gr2Ge2Te6nanostructures stimulated tremendous research interest in both experimental and theoretical studies on various intrinsic magnets at 2D limit. This review gives a comprehensive overview of the recent progress on the emergent 2D magnets and heterostructures. Firstly, several kinds of typical 2D magnetic materials discovered in the last few years and their fabrication methods are summarized in detail. Secondly, the current strategies for manipulating magnetic properties in 2D materials are further discussed. Then, the recent advances on the construction of representative van der Waals magnetic heterostructures and their respective performance are provided. With the hope of motivating the researchers in this area, we finally offered the challenges and outlook on 2D magnetism.
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Affiliation(s)
- Yuyu Yao
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Sino-Danish Center for Education, Beijing 100049, People's Republic of China
| | - Xueying Zhan
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Marshet Getaye Sendeku
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Peng Yu
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Fekadu Tsegaye Dajan
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Chuanchao Zhu
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, People's Republic of China
| | - Ningning Li
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Sino-Danish Center for Education, Beijing 100049, People's Republic of China
| | - Junjun Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Feng Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Zhenxing Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jun He
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
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79
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Gao P, Li X, Yang J. Thickness Dependent Magnetic Transition in Few Layer 1T Phase CrTe 2. J Phys Chem Lett 2021; 12:6847-6851. [PMID: 34279945 DOI: 10.1021/acs.jpclett.1c01901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Room temperature two-dimensional (2D) ferromagnetism is highly desired in practical spintronics applications. Recently, 1T phase CrTe2 (1T-CrTe2) nanosheets with 5 and thicker layers have been successfully synthesized, which all exhibit the properties of ferromagnetic (FM) metals with Curie temperatures around 305 K. However, whether the ferromagnetism therein can be maintained when continuously reducing the nanosheet's thickness to monolayer limit remains unknown. Here, through first-principles calculations, we explore the evolution of magnetic properties of 1 to 6 layer CrTe2 nanosheets and several interesting points are found: First, unexpectedly, monolayer CrTe2 prefers a zigzag antiferromagnetic (AFM) state with its energy much lower than that of FM state. Second, in 2 to 4 layer CrTe2, both the intralayer and interlayer magnetic coupling are AFM. Last, when the number of layers is equal to or greater than 5, the intralayer and interlayer magnetic coupling become FM. Such highly thickness dependent magnetism provides a new perspective to control the magnetic properties of 2D materials.
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Affiliation(s)
- Pengfei Gao
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xingxing Li
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jinlong Yang
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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80
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Tokmachev AM, Averyanov DV, Taldenkov AN, Sokolov IS, Karateev IA, Parfenov OE, Storchak VG. Two-Dimensional Magnets beyond the Monolayer Limit. ACS NANO 2021; 15:12034-12041. [PMID: 34128650 DOI: 10.1021/acsnano.1c03312] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Intrinsic two-dimensional (2D) magnetism has been demonstrated in various materials scaled down to a single monolayer. However, the question is whether 2D magnetism extends beyond the monolayer limit, to chemical species formed by sparse but regular 2D arrays of magnetic atoms. Here we show that sub-monolayer superstructures of Eu atoms self-assembled on the silicon surface exhibit strong magnetic signals. Robust easy-plane magnetism is discovered in both one- and two-dimensionally ordered structures with Eu coverage of half monolayer and above. The emergence of 2D magnetism manifests itself by a strong dependence of the effective transition temperature on weak magnetic fields. The results constitute a versatile platform for miniaturization of 2D magnetic systems and seed an expandable class of atomically thin magnets for applications in information technologies.
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Affiliation(s)
- Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia
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81
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Tan C, Xie WQ, Zheng G, Aloufi N, Albarakati S, Algarni M, Li J, Partridge J, Culcer D, Wang X, Yi JB, Tian M, Xiong Y, Zhao YJ, Wang L. Gate-Controlled Magnetic Phase Transition in a van der Waals Magnet Fe 5GeTe 2. NANO LETTERS 2021; 21:5599-5605. [PMID: 34152781 DOI: 10.1021/acs.nanolett.1c01108] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Magnetic van der Waals (vdW) materials are poised to enable all-electrical control of magnetism in the two-dimensional limit. However, tuning the magnetic ground state in vdW itinerant ferromagnets by voltage-induced charge doping remains a significant challenge, due to the extremely large carrier densities in these materials. Here, by cleaving the vdW itinerant ferromagnet Fe5GeTe2 (F5GT) into 5.4 nm (around two unit cells), we find that the ferromagnetism (FM) in F5GT can be substantially tuned by the thickness. Moreover, by utilizing a solid protonic gate, an electron doping concentration of above 1021 cm-3 has been exhibited in F5GT nanosheets. Such a high carrier accumulation exceeds that possible in widely used electric double-layer transistors (EDLTs) and surpasses the intrinsic carrier density of F5GT. Importantly, it is accompanied by a magnetic phase transition from FM to antiferromagnetism (AFM). The realization of an antiferromagnetic phase in nanosheet F5GT suggests the promise of applications in high-temperature antiferromagnetic vdW devices and heterostructures.
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Affiliation(s)
- Cheng Tan
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Wen-Qiang Xie
- Department of Physics, South China University of Technology, Guangzhou 510640, China
| | - Guolin Zheng
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Nuriyah Aloufi
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Sultan Albarakati
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Meri Algarni
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Junbo Li
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
| | - James Partridge
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Dimitrie Culcer
- School of Physics and ARC Centre of Excellence in Future Low-Energy Electronics Technologies, UNSW Node, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Xiaolin Wang
- Institute for Superconducting & Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
- ARC Centre for Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, New South Wales 2500, Australia
| | - Jia Bao Yi
- Global Innovative Center for Advanced Nanomaterials, School of Engineering, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Mingliang Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
- Department of Physics, School of Physics and Materials Science, Anhui University, Hefei 230601, Anhui, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yimin Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences (CAS), Hefei 230031, Anhui, China
| | - Yu-Jun Zhao
- Department of Physics, South China University of Technology, Guangzhou 510640, China
| | - Lan Wang
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
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82
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Tunable room-temperature ferromagnetism in Co-doped two-dimensional van der Waals ZnO. Nat Commun 2021; 12:3952. [PMID: 34172740 PMCID: PMC8233323 DOI: 10.1038/s41467-021-24247-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 05/28/2021] [Indexed: 11/09/2022] Open
Abstract
The recent discovery of ferromagnetism in two-dimensional van der Waals crystals has provoked a surge of interest in the exploration of fundamental spin interaction in reduced dimensions. However, existing material candidates have several limitations, notably lacking intrinsic room-temperature ferromagnetic order and air stability. Here, motivated by the anomalously high Curie temperature observed in bulk diluted magnetic oxides, we demonstrate room-temperature ferromagnetism in Co-doped graphene-like Zinc Oxide, a chemically stable layered material in air, down to single atom thickness. Through the magneto-optic Kerr effect, superconducting quantum interference device and X-ray magnetic circular dichroism measurements, we observe clear evidences of spontaneous magnetization in such exotic material systems at room temperature and above. Transmission electron microscopy and atomic force microscopy results explicitly exclude the existence of metallic Co or cobalt oxides clusters. X-ray characterizations reveal that the substitutional Co atoms form Co2+ states in the graphitic lattice of ZnO. By varying the Co doping level, we observe transitions between paramagnetic, ferromagnetic and less ordered phases due to the interplay between impurity-band-exchange and super-exchange interactions. Our discovery opens another path to 2D ferromagnetism at room temperature with the advantage of exceptional tunability and robustness.
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83
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Seo J, An ES, Park T, Hwang SY, Kim GY, Song K, Noh WS, Kim JY, Choi GS, Choi M, Oh E, Watanabe K, Taniguchi T, Park JH, Jo YJ, Yeom HW, Choi SY, Shim JH, Kim JS. Tunable high-temperature itinerant antiferromagnetism in a van der Waals magnet. Nat Commun 2021; 12:2844. [PMID: 33990589 PMCID: PMC8121823 DOI: 10.1038/s41467-021-23122-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
Discovery of two dimensional (2D) magnets, showing intrinsic ferromagnetic (FM) or antiferromagnetic (AFM) orders, has accelerated development of novel 2D spintronics, in which all the key components are made of van der Waals (vdW) materials and their heterostructures. High-performing and energy-efficient spin functionalities have been proposed, often relying on current-driven manipulation and detection of the spin states. In this regard, metallic vdW magnets are expected to have several advantages over the widely-studied insulating counterparts, but have not been much explored due to the lack of suitable materials. Here, we report tunable itinerant ferro- and antiferromagnetism in Co-doped Fe4GeTe2 utilizing the vdW interlayer coupling, extremely sensitive to the material composition. This leads to high TN antiferromagnetism of TN ~ 226 K in a bulk and ~210 K in 8 nm-thick nanoflakes, together with tunable magnetic anisotropy. The resulting spin configurations and orientations are sensitively controlled by doping, magnetic field, and thickness, which are effectively read out by electrical conduction. These findings manifest strong merits of metallic vdW magnets as an active component of vdW spintronic applications. Metallic van der Waals magnets have considerable technological promise, due to their ability to be strongly coupled with electronic currents and integrated in two dimensional heterostructures. Here, Seo et al. demonstrate highly tunable itinerant antiferromagnetism in a van der Waals magnet.
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Affiliation(s)
- Junho Seo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Eun Su An
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Taesu Park
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Soo-Yoon Hwang
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Gi-Yeop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Kyung Song
- Materials Modeling and Characterization Department, KIMS, Changwon, Korea
| | - Woo-Suk Noh
- MPPC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, Korea
| | - J Y Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea
| | - Gyu Seung Choi
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Minhyuk Choi
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Eunseok Oh
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - J -H Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea.,MPPC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, Korea
| | - Youn Jung Jo
- Department of Physics, Kyungpook National University, Daegu, Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
| | - Ji Hoon Shim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea. .,Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
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84
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Hu L, Cao L, Li L, Duan J, Liao X, Long F, Zhou J, Xiao Y, Zeng YJ, Zhou S. Two-dimensional magneto-photoconductivity in non-van der Waals manganese selenide. MATERIALS HORIZONS 2021; 8:1286-1296. [PMID: 34821921 DOI: 10.1039/d1mh00009h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Deficient intrinsic species and suppressed Curie temperatures (Tc) in two-dimensional (2D) magnets are major barriers for future spintronic applications. As an alternative, delaminating non-van der Waals (vdW) magnets can offset these shortcomings and involve robust bandgaps to explore 2D magneto-photoconductivity at ambient temperature. Herein, non-vdW α-MnSe2 is first delaminated as quasi-2D nanosheets for the study of emerging semiconductor, ferromagnetism and magneto-photoconductivity behaviors. Abundant nonstoichiometric surfaces induce the renormalization of the band structure and open a bandgap of 1.2 eV. The structural optimization strengthens ferromagnetic super-exchange interactions between the nearest-neighbor Mn2+, which enables us to achieve a high Tc of 320 K well above room temperature. The critical fitting of magnetization and transport measurements both verify that it is of quasi-2D nature. The above observations are evidenced by multiple microscopic and macroscopic characterization tools, in line with the prediction of first-principles calculations. Profiting from the negative magnetoresistance effect, the self-powered infrared magneto-photoconductivity performance including a responsivity of 330.4 mA W-1 and a millisecond-level response speed are further demonstrated. Such merits stem from the synergistic modulation of magnetic and light fields on photogenerated carriers. This provides a new strategy to manipulate both charge and spin in 2D non-vdW systems and displays their alluring prospects in magneto-photodetection.
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Affiliation(s)
- Liang Hu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, Institute of Advanced Magnetic Materials, Hangzhou Dianzi University, Hangzhou 310018, P. R. China.
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85
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Gweon HK, Lee SY, Kwon HY, Jeong J, Chang HJ, Kim KW, Qiu ZQ, Ryu H, Jang C, Choi JW. Exchange Bias in Weakly Interlayer-Coupled van der Waals Magnet Fe 3GeTe 2. NANO LETTERS 2021; 21:1672-1678. [PMID: 33570963 DOI: 10.1021/acs.nanolett.0c04434] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
van der Waals (vdW) magnetic materials provide an ideal platform to study low-dimensional magnetism. However, observations of magnetic characteristics of these layered materials truly distinguishing them from conventional magnetic thin film systems have been mostly lacking. In an effort to investigate magnetic properties unique to vdW magnetic materials, we examine the exchange bias effect, a magnetic phenomenon emerging at the ferromagnetic-antiferromagnetic interface. Exchange bias is observed in the naturally oxidized vdW ferromagnet Fe3GeTe2, owing to an antiferromagnetic ordering in the surface oxide layer. Interestingly, the magnitude and thickness dependence of the effect is unlike those expected in typical thin-film systems. We propose a possible mechanism for this behavior, based on the weak interlayer magnetic coupling inherent to vdW magnets, demonstrating the distinct properties of these materials. Furthermore, the robust and sizable exchange bias for vdW magnets persisting up to relatively high temperatures presents a significant advance for realizing practical two-dimensional spintronics.
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Affiliation(s)
- Hyung Keun Gweon
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Sang Yeop Lee
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Hee Young Kwon
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Juyoung Jeong
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Hye Jung Chang
- Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Nano & Information Technology, KIST school, University of Science and Technology, Seoul 02792, Republic of Korea
| | - Kyoung-Whan Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Zi Qiang Qiu
- Department of Physics, University of California, Berkeley 94720, California, United States
| | - Hyejin Ryu
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Chaun Jang
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jun Woo Choi
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
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86
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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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87
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Liu N, Gallaro CM, Shayan K, Mukherjee A, Kim B, Hone J, Vamivakas N, Strauf S. Antiferromagnetic proximity coupling between semiconductor quantum emitters in WSe 2 and van der Waals ferromagnets. NANOSCALE 2021; 13:832-841. [PMID: 33351877 DOI: 10.1039/d0nr06632j] [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
van der Waals ferromagnets have gained significant interest due to their unique ability to provide magnetic response even at the level of a few monolayers. Particularly in combination with 2D semiconductors, such as the transition metal dichalcogenide WSe2, one can create heterostructures that feature unique magneto-optical response in the exciton emission through the magnetic proximity effect. Here we use 0D quantum emitters in WSe2 to probe for the ferromagnetic response in heterostructures with Fe3GT and Fe5GT ferromagnets through an all-optical read-out technique that does not require electrodes. The spectrally narrow spin-doublet of the WSe2 quantum emitters allowed to fully resolve the hysteretic magneto-response in the exciton emission, revealing the characteristic signature of both ferro- and antiferromagnetic proximity coupling that originates from the interplay among Fe3GT or Fe5GT, a thin surface oxide, and the spin doublets of the quantum emitters. Our work highlights the utility of 0D quantum emitters for probing interface magnetic dipoles in vdW heterostructures with high precision. The observed hysteretic magneto response in the exciton emission of quantum emitters adds further new degrees of freedom for spin and g-factor manipulation of quantum states.
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Affiliation(s)
- Na Liu
- Department of Physics, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA. and Center for Quantum Science and Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA
| | - Cosmo M Gallaro
- Department of Physics, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA. and Center for Quantum Science and Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA
| | - Kamran Shayan
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA and Center for Coherence and Quantum Optics, University of Rochester, Rochester, New York 14627, USA
| | - Arunabh Mukherjee
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA and Center for Coherence and Quantum Optics, University of Rochester, Rochester, New York 14627, USA
| | - Bumho Kim
- Department of Mechanical Engineering, Columbia University, New York 10027, USA
| | - James Hone
- Department of Mechanical Engineering, Columbia University, New York 10027, USA
| | - Nick Vamivakas
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA and Center for Coherence and Quantum Optics, University of Rochester, Rochester, New York 14627, USA and Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - Stefan Strauf
- Department of Physics, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA. and Center for Quantum Science and Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA
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88
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Yang W, Cao Y, Han J, Lin X, Wang X, Wei G, Lv C, Bournel A, Zhao W. Spin-filter induced large magnetoresistance in 2D van der Waals magnetic tunnel junctions. NANOSCALE 2021; 13:862-868. [PMID: 33355579 DOI: 10.1039/d0nr07290g] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) heterostructures, known as layer-by-layer stacked 2D materials in a precisely chosen sequence, have received more and more attention in spintronics for their ultra-clean interface, unique electronic properties and 2D ferromagnetism. Motivated by the recent synthesis of monolayer 1T-VSe2 with ferromagnetic ordering and a high Curie temperature above room temperature, we investigate the bias-voltage driven spin transport properties of 2D magnetic tunnel junctions (MTJs) based on VSe2 utilizing density functional theory combined with the nonequilibrium Green's function method. In the device 1T-MoSe2/1T-VSe2/2H-WSe2/1T-VSe2/1T-MoSe2, the tunneling magneto-resistance (TMR) is incredibly satisfactory up to 5600%. Based on the analysis of evanescent states, this large TMR is attributed to the spin filter effect at the interface between 1T-VSe2 and 2H-WSe2, which overcomes the low spin polarization of 1T-VSe2. Furthermore, by inserting 2H-MoSe2, the spin filter effect is enhanced with decreasing current and the TMR is drastically improved to 1.7 × 105%. This work highlights the feasibility of 2D vdW heterostructures for ultra-low power spintronic applications by electronic structural engineering.
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Affiliation(s)
- Wei Yang
- Fert Beijing Research Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering & Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China.
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89
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Su Y, Li X, Zhu M, Zhang J, You L, Tsymbal EY. Van der Waals Multiferroic Tunnel Junctions. NANO LETTERS 2021; 21:175-181. [PMID: 33264014 DOI: 10.1021/acs.nanolett.0c03452] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Multiferroic tunnel junctions (MFTJs) have aroused significant interest due to their functional properties useful for nonvolatile memory devices. So far, however, all of the existing MFTJs have been based on perovskite-oxide heterostructures limited by a relatively high resistance-area (RA) product unfavorable for practical applications. Here, using first-principles calculations, we explore spin-dependent transport properties of van der Waals (vdW) MFTJs which consist of two-dimensional (2D) ferromagnetic FenGeTe2 (n = 3, 4, 5) electrodes and 2D ferroelectric In2Se3 barrier layers. We demonstrate that such FemGeTe2/In2Se3/FenGeTe2 (m, n = 3, 4, 5; m ≠ n) MFTJs exhibit multiple nonvolatile resistance states associated with different polarization orientation of the ferroelectric In2Se3 layer and magnetization alignment of the two ferromagnetic FenGeTe2 layers. We find a remarkably low RA product (less than 1 Ω·μm2) which makes the proposed vdW MFTJs superior to the conventional MFTJs in terms of their promise for nonvolatile memory applications.
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Affiliation(s)
- Yurong Su
- School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Xinlu Li
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Meng Zhu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jia Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Long You
- School of Optical and Electronic Information, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, United States
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90
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Yang S, Zhang T, Jiang C. van der Waals Magnets: Material Family, Detection and Modulation of Magnetism, and Perspective in Spintronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002488. [PMID: 33511010 PMCID: PMC7816723 DOI: 10.1002/advs.202002488] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/09/2020] [Indexed: 06/02/2023]
Abstract
van der Waals (vdW) materials exhibit great potential in spintronics, arising from their excellent spin transportation, large spin-orbit coupling, and high-quality interfaces. The recent discovery of intrinsic vdW antiferromagnets and ferromagnets has laid the foundation for the construction of all-vdW spintronic devices, and enables the study of low-dimensional magnetism, which is of both technical and scientific significance. In this review, several representative families of vdW magnets are introduced, followed by a comprehensive summary of the methods utilized in reading out the magnetic states of vdW magnets. Thereafter, it is shown that various electrical, mechanical, and chemical approaches are employed to modulate the magnetism of vdW magnets. Finally, the perspective of vdW magnets in spintronics is discussed and an outlook of future development direction in this field is also proposed.
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Affiliation(s)
- Shengxue Yang
- School of Materials Science and EngineeringBeihang UniversityBeijing100191P. R. China
| | - Tianle Zhang
- School of Materials Science and EngineeringBeihang UniversityBeijing100191P. R. China
| | - Chengbao Jiang
- School of Materials Science and EngineeringBeihang UniversityBeijing100191P. R. China
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91
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Gao Y, Yin Q, Wang Q, Li Z, Cai J, Zhao T, Lei H, Wang S, Zhang Y, Shen B. Spontaneous (Anti)meron Chains in the Domain Walls of van der Waals Ferromagnetic Fe 5- x GeTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2005228. [PMID: 33118243 DOI: 10.1002/adma.202005228] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/03/2020] [Indexed: 06/11/2023]
Abstract
The promise of topologically vortex-like magnetic spin textures hinges on the intriguing physical properties and theories in fundamental research and their distinguished roles as high-efficiency information units in future spintronics. The exploration of such magnetic states with unique spin configurations has never ceased. In this study, the emergence of unconventional (anti)meron chains from a domain wall pair is directly observed at zero field in 2D ferromagnetic Fe5- x GeTe2 , closely correlated with significant enhancement of the in-plane magnetization and weak van der Waals interactions. The simultaneous appearance of a large topological Hall effect is observed at the same temperature range as that of the abnormal magnetic transition. Moreover, the distinctive features of the (anti)meron chains and their collective dynamic behavior under external fields may provide concrete experimental evidence for the recent theoretical prediction of the magnetic-domain-wall topology and endorse a broader range of possibilities for electronics, spintronics, condensed matter physics, etc.
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Affiliation(s)
- Yang Gao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Institute of Advanced Materials, Beijing Normal University, Beijing, 100875, China
| | - Qiangwei Yin
- Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Qi Wang
- Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Zhuolin Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Shouguo Wang
- Institute of Advanced Materials, Beijing Normal University, Beijing, 100875, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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92
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Huang B, McGuire MA, May AF, Xiao D, Jarillo-Herrero P, Xu X. Emergent phenomena and proximity effects in two-dimensional magnets and heterostructures. NATURE MATERIALS 2020; 19:1276-1289. [PMID: 32948831 DOI: 10.1038/s41563-020-0791-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 07/30/2020] [Indexed: 05/24/2023]
Abstract
Ultrathin van der Waals materials and their heterostructures offer a simple, yet powerful platform for discovering emergent phenomena and implementing device structures in the two-dimensional limit. The past few years has pushed this frontier to include magnetism. These advances have brought forth a new assortment of layered materials that intrinsically possess a wide variety of magnetic properties and are instrumental in integrating exchange and spin-orbit interactions into van der Waals heterostructures. This Review Article summarizes recent progress in exploring the intrinsic magnetism of atomically thin van der Waals materials, manipulation of their magnetism by tuning the interlayer coupling, and device structures for spin- and valleytronic applications.
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Affiliation(s)
- Bevin Huang
- Department of Physics, University of Washington, Seattle, WA, USA.
| | - Michael A McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
| | | | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
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93
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Pham YTH, Liu M, Jimenez VO, Yu Z, Kalappattil V, Zhang F, Wang K, Williams T, Terrones M, Phan MH. Tunable Ferromagnetism and Thermally Induced Spin Flip in Vanadium-Doped Tungsten Diselenide Monolayers at Room Temperature. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003607. [PMID: 33015889 DOI: 10.1002/adma.202003607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/19/2020] [Indexed: 05/27/2023]
Abstract
The outstanding optoelectronic and valleytronic properties of transition metal dichalcogenides (TMDs) have triggered intense research efforts by the scientific community. An alternative to induce long-range ferromagnetism (FM) in TMDs is by introducing magnetic dopants to form a dilute magnetic semiconductor. Enhancing ferromagnetism in these semiconductors not only represents a key step toward modern TMD-based spintronics, but also enables exploration of new and exciting dimensionality-driven magnetic phenomena. To this end, tunable ferromagnetism at room temperature and a thermally induced spin flip (TISF) in monolayers of V-doped WSe2 are shown. As vanadium concentration increases, the saturation magnetization increases, which is optimal at ≈4 at% vanadium; the highest doping level ever achieved for V-doped WSe2 monolayers. The TISF occurs at ≈175 K and becomes more pronounced upon increasing the temperature toward room temperature. The TISF can be manipulated by changing the vanadium concentration. The TISF is attributed to the magnetic-field- and temperature-dependent flipping of the nearest W-site magnetic moments that are antiferromagnetically coupled to the V magnetic moments in the ground state. This is fully supported by a recent spin-polarized density functional theory study. The findings pave the way for the development of novel spintronic and valleytronic nanodevices and stimulate further research.
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Affiliation(s)
- Yen Thi Hai Pham
- Department of Physics, University of South Florida, Tampa, FL, 33620, USA
| | - Mingzu Liu
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Two Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Zhuohang Yu
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Fu Zhang
- Center for Two Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ke Wang
- Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Teague Williams
- Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mauricio Terrones
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Two Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Manh-Huong Phan
- Department of Physics, University of South Florida, Tampa, FL, 33620, USA
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94
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Li Z, Xia W, Su H, Yu Z, Fu Y, Chen L, Wang X, Yu N, Zou Z, Guo Y. Magnetic critical behavior of the van der Waals Fe 5GeTe 2 crystal with near room temperature ferromagnetism. Sci Rep 2020; 10:15345. [PMID: 32948794 PMCID: PMC7501290 DOI: 10.1038/s41598-020-72203-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/27/2020] [Indexed: 12/03/2022] Open
Abstract
The van der Waals ferromagnet Fe5GeTe2 has a Curie temperature TC of about 270 K, which is tunable through controlling the Fe deficiency content and can even reach above room temperature. To achieve insights into its ferromagnetic exchange that gives the high TC, the critical behavior has been investigated by measuring the magnetization in Fe5GeTe2 crystal around the ferromagnetic ordering temperature. The analysis of the measured magnetization by using various techniques harmonically reached to a set of reliable critical exponents with TC = 273.7 K, β = 0.3457 ± 0.001, γ = 1.40617 ± 0.003, and δ = 5.021 ± 0.001. By comparing these critical exponents with those predicted by various models, it seems that the magnetic properties of Fe5GeTe2 could be interpreted by a three-dimensional magnetic exchange with the exchange distance decaying as J(r) ≈ r−4.916, close to that of a three-dimensional Heisenberg model with long-range magnetic coupling.
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Affiliation(s)
- Zhengxian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hao Su
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenhai Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yunpeng Fu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Leiming Chen
- School of Materials Science and Engineering, Henan Key Laboratory of Aeronautic Materials and Application Technology, Zhengzhou University of Aeronautics, Zhengzhou, 450046, Henan, China.
| | - Xia Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Analytical Instrumentation Center, School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Na Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Analytical Instrumentation Center, School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Zhiqiang Zou
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.,Analytical Instrumentation Center, School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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95
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Abstract
CeTe3 is a unique platform to investigate the itinerant magnetism in a van der Waals (vdW) coupled metal. Despite chemical pressure being a promising route to boost quantum fluctuation in this system, a systematic study on the chemical pressure effect on Ce3+(4f1) states is absent. Here, we report on the successful growth of a series of Se doped single crystals of CeTe3. We found a fluctuation driven exotic magnetic rotation from the usual easy-axis ordering to an unusual hard-axis ordering. Unlike in localized magnetic systems, near-critical magnetism can increase itinerancy hand-in-hand with enhancing fluctuation of magnetism. Thus, seemingly unstable hard-axis ordering emerges through kinetic energy gain, with the self-consistent observation of enhanced magnetic fluctuation (disorder). As far as we recognize, this order-by-disorder process in fermionic system is observed for the first time within vdW materials. Our finding opens a unique experimental platform for direct visualization of the rich quasiparticle Fermi surface deformation associated with the Fermionic order-by-disorder process. Also, the search for emergent exotic phases by further tuning of quantum fluctuation is suggested as a promising future challenge.
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96
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Wang H, Liu Y, Wu P, Hou W, Jiang Y, Li X, Pandey C, Chen D, Yang Q, Wang H, Wei D, Lei N, Kang W, Wen L, Nie T, Zhao W, Wang KL. Above Room-Temperature Ferromagnetism in Wafer-Scale Two-Dimensional van der Waals Fe 3GeTe 2 Tailored by a Topological Insulator. ACS NANO 2020; 14:10045-10053. [PMID: 32686930 DOI: 10.1021/acsnano.0c03152] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The emerging two-dimensional ferromagnetic materials present atomic layer thickness and a perfect interface feature, which have become an attractive research direction in the field of spintronics for low power and deep nanoscale integration. However, it has been proven to be extremely challenging to achieve a room-temperature ferromagnetic candidate with well controlled dimensionality, large-scale production, and convenient heterogeneous integration. Here, we report the growth of wafer-scale two-dimensional Fe3GeTe2 integrated with a topological insulator of Bi2Te3 by molecular beam epitaxy, which shows a Curie temperature (Tc) up to 400 K with perpendicular magnetic anisotropy. Dimensionality-dependent magnetic and magnetotransport measurements find that Tc increases with decreasing Fe3GeTe2 thickness in the heterostructures, indicating an interfacial engineering effect from Bi2Te3. The theoretical calculation further proves that the interfacial exchange coupling could significantly enhance the intralayer spin interaction in Fe3GeTe2, hence giving rise to a higher Tc. Our results provide great potential for the implementation of high-performance spintronic devices based on two-dimensional ferromagnetic materials.
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Affiliation(s)
- Haiyu Wang
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Yingjie Liu
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Peichen Wu
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Wenjie Hou
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Yuhao Jiang
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Xiaohui Li
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Chandan Pandey
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Dongdong Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
| | - Qing Yang
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Hangtian Wang
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Dahai Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
| | - Na Lei
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Wang Kang
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
| | - Lianggong Wen
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Tianxiao Nie
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Weisheng Zhao
- School of Microelectronics and Advanced Innovation Center for Big Data and Brain Computing, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Kang L Wang
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, United States
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97
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Cai S, Yang F, Gao C. FeCl 2 monolayer on HOPG: art of growth and momentum filtering effect. NANOSCALE 2020; 12:16041-16045. [PMID: 32706361 DOI: 10.1039/d0nr03128c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Magnetic layered transition metal halides have received intensive attention due to the potential magnetic properties in their monolayers. Following the recently reported success of trihalide monolayer ferromagnets, we have achieved the growth of a dihalide, FeCl2, monolayer system on graphite by molecular beam epitaxy. Scanning tunneling microscopy was used in the topographic and spectroscopic study of the monolayer islands at the atomic scale. Results show that the FeCl2 monolayer is an electronvolt-gaped insulator with various twist angles relative to the substrate. The tunneling probability on the monolayer islands is a function of the twist angle with a max/min ratio of ∼2.5. Our direct experimental evidence finds that the FeCl2 monolayer is an efficient momentum, perhaps spin, filtering insulating layer with subnanometer thickness.
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Affiliation(s)
- Shihao Cai
- School of Physics and Astronomy, Shanghai Jiao Tong University, Dongchuan Rd. 800, 200240 Shanghai, P.R. China
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98
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Purbawati A, Coraux J, Vogel J, Hadj-Azzem A, Wu N, Bendiab N, Jegouso D, Renard J, Marty L, Bouchiat V, Sulpice A, Aballe L, Foerster M, Genuzio F, Locatelli A, Menteş TO, Han ZV, Sun X, Núñez-Regueiro M, Rougemaille N. In-Plane Magnetic Domains and Néel-like Domain Walls in Thin Flakes of the Room Temperature CrTe 2 Van der Waals Ferromagnet. ACS APPLIED MATERIALS & INTERFACES 2020; 12:30702-30710. [PMID: 32515190 DOI: 10.1021/acsami.0c07017] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The recent discovery of magnetic van der Waals (vdW) materials triggered a wealth of investigations in materials science and now offers genuinely new prospects for both fundamental and applied research. Although the catalog of vdW ferromagnets is rapidly expanding, most of them have a Curie temperature below 300 K, a notable disadvantage for potential applications. Combining element-selective X-ray magnetic imaging and magnetic force microscopy, we resolve at room temperature the magnetic domains and domain walls in micron-sized flakes of the CrTe2 vdW ferromagnet. Flux-closure magnetic patterns suggesting an in-plane six-fold symmetry are observed. Upon annealing the material above its Curie point (315 K), the magnetic domains disappear. By cooling back the sample, a different magnetic domain distribution is obtained, indicating material stability and lack of magnetic memory upon thermal cycling. The domain walls presumably have Néel texture, are preferentially oriented along directions separated by 120°, and have a width of several tens of nanometers. Besides microscopic mapping of magnetic domains and domain walls, the coercivity of the material is found to be of a few millitesla only, showing that the CrTe2 compound is magnetically soft. The coercivity is found to increase as the volume of the material decreases.
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Affiliation(s)
- Anike Purbawati
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Johann Coraux
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Jan Vogel
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | | | - NianJheng Wu
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Nedjma Bendiab
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - David Jegouso
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Julien Renard
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Laetitia Marty
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Vincent Bouchiat
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - André Sulpice
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
| | - Lucia Aballe
- ALBA Synchrotron Light Facility, 08290 Cerdanyola Del Valles, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, 08290 Cerdanyola Del Valles, Spain
| | - Francesca Genuzio
- Elettra-Sincrotrone Trieste S.C.p.A., S:S. 14, km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - Andrea Locatelli
- Elettra-Sincrotrone Trieste S.C.p.A., S:S. 14, km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone Trieste S.C.p.A., S:S. 14, km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - Zheng Vitto Han
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui 230026, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, P. R.China
| | - Xingdan Sun
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui 230026, China
| | | | - Nicolas Rougemaille
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, 38000 Grenoble, France
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99
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Xu R, Zou X. Electric Field-Modulated Magnetic Phase Transition in van der Waals CrI 3 Bilayers. J Phys Chem Lett 2020; 11:3152-3158. [PMID: 32239941 DOI: 10.1021/acs.jpclett.0c00567] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional van der Waals (vdW) magnetic materials are well-recognized milestones toward nanostructured spintronics. An interesting example is CrI3; its magnetic states can be modulated electrically, allowing spintronics applications that are highly compatible with electronics technologies. Here, we report the electric field alone induces the interlayer antiferromagnetic-to-ferromagnetic (AFM-to-FM) phase transition in CrI3 bilayers with critical field as low as 0.12 V/Å. The AFM-FM energy difference ΔE increases with electric field and is closely related to the field-induced on-site energy difference defined as the splitting between the electronic states of the two vdW layers. Our tight-binding model fits closely with ΔE as a function of electric field and gives a consistent estimation for orbital hopping, exchange splitting, and crystal field splitting. Furthermore, a CrI3-based spin field-effect device is suggested with the spin current switched on and off solely by the electric field. These findings not only reveal the physics underlying the transition but also provide guidelines for future discovery and design.
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Affiliation(s)
- Runzhang Xu
- Shenzhen Geim Graphene Center and Low-dimensional Materials and Devices Laboratory, Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, P. R. China
| | - Xiaolong Zou
- Shenzhen Geim Graphene Center and Low-dimensional Materials and Devices Laboratory, Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, P. R. China
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100
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Seo J, Kim DY, An ES, Kim K, Kim GY, Hwang SY, Kim DW, Jang BG, Kim H, Eom G, Seo SY, Stania R, Muntwiler M, Lee J, Watanabe K, Taniguchi T, Jo YJ, Lee J, Min BI, Jo MH, Yeom HW, Choi SY, Shim JH, Kim JS. Nearly room temperature ferromagnetism in a magnetic metal-rich van der Waals metal. SCIENCE ADVANCES 2020; 6:eaay8912. [PMID: 32010775 PMCID: PMC6968938 DOI: 10.1126/sciadv.aay8912] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/12/2019] [Indexed: 05/30/2023]
Abstract
In spintronics, two-dimensional van der Waals crystals constitute a most promising material class for long-distance spin transport or effective spin manipulation at room temperature. To realize all-vdW-material-based spintronic devices, however, vdW materials with itinerant ferromagnetism at room temperature are needed for spin current generation and thereby serve as an effective spin source. We report theoretical design and experimental realization of a iron-based vdW material, Fe4GeTe2, showing a nearly room temperature ferromagnetic order, together with a large magnetization and high conductivity. These properties are well retained even in cleaved crystals down to seven layers, with notable improvement in perpendicular magnetic anisotropy. Our findings highlight Fe4GeTe2 and its nanometer-thick crystals as a promising candidate for spin source operation at nearly room temperature and hold promise to further increase T c in vdW ferromagnets by theory-guided material discovery.
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Affiliation(s)
- Junho Seo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Duck Young Kim
- Center for High Pressure Science and Technology Advanced Research, Shanghai, China
| | - Eun Su An
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Kyoo Kim
- Max Planck POSTECH/Hsinchu Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang, Korea
| | - Gi-Yeop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Soo-Yoon Hwang
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Dong Wook Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Bo Gyu Jang
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Heejung Kim
- Max Planck POSTECH/Hsinchu Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang, Korea
| | - Gyeongsik Eom
- Department of Physics, Ajou University, Suwon 16499, Korea
| | - Seung Young Seo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Roland Stania
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
| | | | - Jinwon Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Youn Jung Jo
- Department of Physics, Kyungpook National University, Daegu 41566, Korea
| | - Jieun Lee
- Department of Physics, Ajou University, Suwon 16499, Korea
| | - Byung Il Min
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Moon Ho Jo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Ji Hoon Shim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
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