1
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Wu Y, Zhang D, Zhang YN, Deng L, Peng B. Nonreciprocal and Nonvolatile Electric-Field Switching of Magnetism in van der Waals Heterostructure Multiferroics. Nano Lett 2024. [PMID: 38655909 DOI: 10.1021/acs.nanolett.3c03970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Multiferroic materials provide robust and efficient routes for the control of magnetism by electric fields, which have been diligently sought after for a long time. Construction of two-dimensional (2D) vdW multiferroics is a more exciting endeavor. To date, the nonvolatile manipulation of magnetism through ferroelectric polarization still remains challenging in a 2D vdW heterostructure multiferroic. Here, we report a van der Waals (vdW) heterostructure multiferroic comprising the atomically thin layered antiferromagnet (AFM) CrI3 and ferroelectric (FE) α-In2Se3. We demonstrate anomalously nonreciprocal and nonvolatile electric-field control of magnetization by ferroelectric polarization. The nonreciprocal electric control originates from an intriguing antisymmetric enhancement of interlayer ferromagnetic coupling in the opposite ferroelectric polarization configurations of α-In2Se3. Our work provides numerous possibilities for creating diverse heterostructure multiferroics at the limit of a few atomic layers for multistage magnetic memories and brain-inspired in-memory computing.
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Affiliation(s)
- Yangliu Wu
- 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, People's Republic of China
- Key Laboratory of Multi Spectral Absorbing Materials and Structures of Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China
| | - Deju Zhang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China
| | - Yan-Ning Zhang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of 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, People's Republic of China
- Key Laboratory of Multi Spectral Absorbing Materials and Structures of Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China
| | - 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, People's Republic of China
- Key Laboratory of Multi Spectral Absorbing Materials and Structures of Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China
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2
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Kumari P, Majumder S, Kar S, Rani S, Nair AK, Kumari K, Kamalakar MV, Ray SJ. An all phosphorene lattice nanometric spin valve. Sci Rep 2024; 14:9138. [PMID: 38644366 PMCID: PMC11033266 DOI: 10.1038/s41598-024-58589-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 04/01/2024] [Indexed: 04/23/2024] Open
Abstract
Phosphorene is a unique semiconducting two-dimensional platform for enabling spintronic devices integrated with phosphorene nanoelectronics. Here, we have designed an all phosphorene lattice lateral spin valve device, conceived via patterned magnetic substituted atoms of 3d-block elements at both ends of a phosphorene nanoribbon acting as ferromagnetic electrodes in the spin valve. Through First-principles based calculations, we have extensively studied the spin-dependent transport characteristics of the new spin valve structures. Systematic exploration of the magnetoresistance (MR) of the spin valve for various substitutional atoms and bias voltage resulted in a phase diagram offering a colossal MR for V and Cr-substitutional atoms. Such MR can be directly attributed to their specific electronic structure, which can be further tuned by a gate voltage, for electric field controlled spin valves. The spin-dependent transport characteristics here reveal new features such as negative conductance oscillation and switching of the sign of MR due to change in the majority spin carrier type. Our study creates possibilities for the design of nanometric spin valves, which could enable integration of memory and logic elements for all phosphorene 2D processors.
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Affiliation(s)
- P Kumari
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - S Majumder
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - S Kar
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - S Rani
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - A K Nair
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - K Kumari
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India
| | - M Venkata Kamalakar
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden
| | - S J Ray
- Department of Physics, Indian Institute of Technology Patna, Bihta, 801103, India.
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3
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Tang X, Zhou J, Wong NLM, Chai J, Liu Y, Wang S, Song X. Strain-Induced Ferromagnetism in Monolayer T″-Phase VTe 2: Unveiling Magnetic States and Anisotropy for Spintronics Advancement. Nanomaterials (Basel) 2024; 14:704. [PMID: 38668198 PMCID: PMC11054831 DOI: 10.3390/nano14080704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/14/2024] [Accepted: 04/15/2024] [Indexed: 04/29/2024]
Abstract
Two-dimensional (2D) ferromagnets have attracted significant interest for their potential in spintronic device miniaturization, especially since the discovery of ferromagnetic ordering in monolayer materials such as CrI3 and Fe3GeTe2 in 2017. This study presents a detailed investigation into the effects of the Hubbard U parameter, biaxial strain, and structural distortions on the magnetic characteristics of T″-phase VTe2. We demonstrate that setting the Hubbard U to 0 eV provides an accurate representation of the observed structural, magnetic, and electronic features for both bulk and monolayer T″-phase VTe2. The application of strain reveals two distinct ferromagnetic states in the monolayer T″-phase VTe2, each characterized by minor structural differences, but notably different magnetic moments. The T″-1 state, with reduced magnetic moments, emerges under compressive strain, while the T″-2 state, featuring increased magnetic moments, develops under tensile strain. Our analysis also compares the magnetic anisotropy between the T and T″ phases of VTe2, highlighting that the periodic lattice distortion in the T″-phase induces an in-plane anisotropy, which makes it a material with an easy-axis of magnetization. Monte Carlo simulations corroborate our findings, indicating a high Curie temperature of approximately 191 K for the T″-phase VTe2. Our research not only sheds light on the critical aspects of the VTe2 system but also suggests new pathways for enhancing low-dimensional magnetism, contributing to the advancement of spintronics and straintronics.
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Affiliation(s)
- Xiaoting Tang
- Department of Physics, College of Science, Shanghai University, 99 Shangda Road, Shanghai 200444, China;
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Jun Zhou
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore; (J.Z.); (N.L.M.W.); (J.C.)
| | - Nancy Lai Mun Wong
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore; (J.Z.); (N.L.M.W.); (J.C.)
| | - Jianwei Chai
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore; (J.Z.); (N.L.M.W.); (J.C.)
| | - Yi Liu
- Department of Physics, College of Science, Shanghai University, 99 Shangda Road, Shanghai 200444, China;
- Materials Genome Institute (MGI), Shanghai University, 333 Nanchen Road, Shanghai 200444, China
| | - Shijie Wang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore; (J.Z.); (N.L.M.W.); (J.C.)
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4
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Fu Z, Samarawickrama PI, Zhu Y, Mao Z, Wang W, Watanabe K, Taniguchi T, Tang J, Ackerman J, Tian J. Nonvolatile Memristive Effect in Few-Layer CrI 3 Driven by Electrostatic Gating. Nano Lett 2023; 23:11866-11873. [PMID: 38079362 DOI: 10.1021/acs.nanolett.3c03926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
The potential of memristive devices for applications in nonvolatile memory and neuromorphic computing has sparked considerable interest, particularly in exploring memristive effects in two-dimensional (2D) magnetic materials. However, the progress in developing nonvolatile, magnetic field-free memristive devices using 2D magnets has been limited. In this work, we report an electrostatic-gating-induced nonvolatile memristive effect in CrI3-based tunnel junctions. The few-layer CrI3-based tunnel junction manifests notable hysteresis in its tunneling resistance as a function of gate voltage. We further engineered a nonvolatile memristor using the CrI3 tunneling junction with low writing power and at zero magnetic field. We show that the hysteretic transport observed is not a result of trivial effects or inherent magnetic properties of CrI3. We propose a potential association between the memristive effect and the newly predicted ferroelectricity in CrI3 via gating-induced Jahn-Teller distortion. Our work illuminates the potential of 2D magnets in developing next-generation advanced computing technologies.
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Affiliation(s)
- ZhuangEn Fu
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Piumi I Samarawickrama
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Yanglin Zhu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zhiqiang Mao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Wenyong Wang
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Jinke Tang
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
| | - John Ackerman
- Department of Chemical and Biomedical Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Jifa Tian
- Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071, United States
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
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5
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Kim J, Na W, Kim J, Park P, Zhang K, Hwang I, Son YW, Kim JH, Cheong H, Park JG. Rapid Suppression of Quantum Many-Body Magnetic Exciton in Doped van der Waals Antiferromagnet (Ni,Cd)PS 3. Nano Lett 2023; 23:10189-10195. [PMID: 37931216 DOI: 10.1021/acs.nanolett.3c02677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The unique discovery of the magnetic exciton in van der Waals antiferromagnet NiPS3 arises between two quantum many-body states of a Zhang-Rice singlet excited state and a Zhang-Rice triplet ground state. Simultaneously, the spectral width of photoluminescence originating from this exciton is exceedingly narrow as 0.4 meV. These extraordinary properties, including the extreme coherence of the magnetic exciton in NiPS3, beg many questions. We studied doping effects using Ni1-xCdxPS3 using two experimental techniques and theoretical studies. Our experimental results show that the magnetic exciton is drastically suppressed upon a few % Cd doping. All this happens while the width of the exciton only gradually increases and the antiferromagnetic ground state is robust. These results highlight the lattice uniformity's hidden importance as a prerequisite for coherent magnetic exciton. Finally, an exciting scenario emerges: the broken charge transfer forbids the otherwise uniform formation of the coherent magnetic exciton in (Ni,Cd)PS3.
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Affiliation(s)
- Junghyun Kim
- Center for Quantum Materials, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Woongki Na
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Jonghyeon Kim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Pyeongjae Park
- Center for Quantum Materials, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Kaixuan Zhang
- Center for Quantum Materials, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Inho Hwang
- Center for Quantum Materials, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Young-Woo Son
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - Jae Hoon Kim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Je-Geun Park
- Center for Quantum Materials, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul 08826, Republic of Korea
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6
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Liu S, Malik IA, Zhang VL, Yu T. Lightning the Spin: Harnessing the Potential of 2D Magnets in Opto-Spintronics. Adv Mater 2023:e2306920. [PMID: 37905890 DOI: 10.1002/adma.202306920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/20/2023] [Indexed: 11/02/2023]
Abstract
Since the emergence of 2D magnets in 2017, the diversity of these materials has greatly expanded. Their 2D nature (atomic-scale thickness) endows these magnets with strong magnetic anisotropy, layer-dependent and switchable magnetic order, and quantum-confined quasiparticles, which distinguish them from conventional 3D magnetic materials. Moreover, the 2D geometry facilitates light incidence for opto-spintronic applications and potential on-chip integration. In analogy to optoelectronics based on optical-electronic interactions, opto-spintronics use light-spin interactions to process spin information stored in the solid state. In this review, opto-spintronics is divided into three types with respect to the wavelengths of radiation interacting with 2D magnets: 1) GHz (microwave) to THz (mid-infrared), 2) visible, and 3) UV to X-rays. It is focused on the recent research advancements on the newly discovered mechanisms of light-spin interactions in 2D magnets and introduces the potential design of novel opto-spintronic applications based on these interactions.
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Affiliation(s)
- Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | | | - Vanessa Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
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7
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Tseng CC, Song T, Jiang Q, Lin Z, Wang C, Suh J, Watanabe K, Taniguchi T, McGuire MA, Xiao D, Chu JH, Cobden DH, Xu X, Yankowitz M. Gate-Tunable Proximity Effects in Graphene on Layered Magnetic Insulators. Nano Lett 2022; 22:8495-8501. [PMID: 36279401 DOI: 10.1021/acs.nanolett.2c02931] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The extreme versatility of van der Waals materials originates from their ability to exhibit new electronic properties when assembled in close proximity to dissimilar crystals. For example, although graphene is inherently nonmagnetic, recent work has reported a magnetic proximity effect in graphene interfaced with magnetic substrates, potentially enabling a pathway toward achieving a high-temperature quantum anomalous Hall effect. Here, we investigate heterostructures of graphene and chromium trihalide magnetic insulators (CrI3, CrBr3, and CrCl3). Surprisingly, we are unable to detect a magnetic exchange field in the graphene but instead discover proximity effects featuring unprecedented gate tunability. The graphene becomes highly hole-doped due to charge transfer from the neighboring magnetic insulator and further exhibits a variety of atypical gate-dependent transport features. The charge transfer can additionally be altered upon switching the magnetic states of the nearest CrI3 layers. Our results provide a roadmap for exploiting proximity effects arising in graphene coupled to magnetic insulators.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Michael A McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Di Xiao
- Pacific Northwest National Laboratory, Richland, Washington99354, United States
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8
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Liu W, Guo X, Schwartz J, Xie H, Dhale NU, Sung SH, Kondusamy ALN, Wang X, Zhao H, Berman D, Hovden R, Zhao L, Lv B. A Three-Stage Magnetic Phase Transition Revealed in Ultrahigh-Quality van der Waals Bulk Magnet CrSBr. ACS Nano 2022; 16:15917-15926. [PMID: 36149801 DOI: 10.1021/acsnano.2c02896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
van der Waals (vdW) magnets are receiving ever-growing attention nowadays due to their significance in both fundamental research on low-dimensional magnetism and potential applications in spintronic devices. The high crystalline quality of vdW magnets is the key to maintaining intrinsic magnetic and electronic properties, especially when exfoliated down to the two-dimensional limit. Here, ultrahigh-quality air-stable vdW CrSBr crystals are synthesized using the direct solid-vapor synthesis method. The high single crystallinity and spatial homogeneity have been thoroughly evidenced at length scales from submm to atomic resolution by X-ray diffraction, second harmonic generation, and scanning transmission electron microscopy. More importantly, specific heat measurements of ultrahigh-quality CrSBr crystals show three thermodynamic anomalies at 185, 156, and 132 K, revealing a stage-by-stage development of the magnetic order upon cooling, which is also corroborated with the magnetization and transport results. Our ultrahigh-quality CrSBr can further be exfoliated down to monolayers and bilayers easily, providing the building blocks of heterostructures for spintronic and magneto-optoelectronic applications.
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Affiliation(s)
- Wenhao Liu
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Xiaoyu Guo
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jonathan Schwartz
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hongchao Xie
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nikhil Uday Dhale
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Suk Hyun Sung
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Xiqu Wang
- Department of Chemistry, University of Houston, Houston, Texas 77004, United States
| | - Haonan Zhao
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Diana Berman
- Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States
| | - Robert Hovden
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Liuyan Zhao
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Bing Lv
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 United States
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9
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Abstract
Two-dimensional (2D) van der Waals ferromagnets carry the promise of ultimately miniature spintronics and information storage devices. Among the 2D ferromagnets, all inherit the magnetic ordering from their bulk ancestors. Here we report a 2D ferromagnetic semiconductor at room temperature, 2H-phase vanadium diselenide (VSe2), which shows ferromagnetic at the 2D form only. This 2D ferromagnetic semiconductor manifests an enhanced magnetic ordering owing to structural anisotropy at the 2D limit.
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Affiliation(s)
- Xiong Wang
- Physics Department, University of Hong Kong, Hong Kong 999077, People's Republic of China
| | - Dian Li
- Physics Department, University of Hong Kong, Hong Kong 999077, People's Republic of China
| | - Zejun Li
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Changzheng Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Chi-Ming Che
- Department of Chemistry, State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, People's Republic of China
| | - Gang Chen
- Physics Department, University of Hong Kong, Hong Kong 999077, People's Republic of China
| | - Xiaodong Cui
- Physics Department, University of Hong Kong, Hong Kong 999077, People's Republic of China
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10
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Zhang Q, Hwangbo K, Wang C, Jiang Q, Chu JH, Wen H, Xiao D, Xu X. Observation of Giant Optical Linear Dichroism in a Zigzag Antiferromagnet FePS 3. Nano Lett 2021; 21:6938-6945. [PMID: 34428905 DOI: 10.1021/acs.nanolett.1c02188] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Direct optical probing of the antiferromagnetic order parameter in atomically thin samples is challenging, for example, via magneto-optical spectroscopy, due to the lack of net magnetization. Here, we report zigzag-antiferromagnetism (AFM) induced optical linear dichroism (LD) in layered transition-metal thiophosphate FePS3 down to the monolayer limit. The observed LD is giant despite having the optical wave vector parallel to the Néel vector. The LD is at least one order of magnitude larger than those reported in other antiferromagnetic systems, where the optical wave vector is orthogonal to the Néel vector. The large LD enables the probe of 60° orientated zigzag-AFM domains. The optical anisotropy in FePS3 originates from an electronic anisotropy associated with the zigzag direction of the AFM order and is independent of the spin-pointing direction. Our findings point to a new optical approach for the investigation and control of zigzag or stripe magnetic order in strongly correlated systems.
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Affiliation(s)
- Qi Zhang
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kyle Hwangbo
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Chong Wang
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Qianni Jiang
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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11
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Abstract
Heterostructures of two-dimensional transition-metal dichalcogenides and ferromagnetic substrates are important candidates for the development of viable new spin- or valleytronic devices. For the prototypical bilayer of WSe2 on top of a ferromagnetic layer of CrI3, we find substantially different coupling of both WSe2 K-valleys to the sublayer. Besides an energy splitting of a few meV, the corresponding excitons have significantly different interlayer character with charge transfer allowed at the K̅- point but forbidden at K̅+. The different exciton wave functions result in a distinctly different response to magnetic fields with g factors of about -4.4 and -4.0, respectively. By means of ab initio GW/Bethe-Salpeter equation calculations, these findings establish g factors as tool for investigating the exciton character and shedding light on the detailed quantum-mechanical interplay of magnetic and optical properties which are essential for the targeted development of optoelectronic devices.
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Affiliation(s)
| | - Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Peter Krüger
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
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12
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Zhang XX, Jiang S, Lee J, Lee C, Mak KF, Shan J. Spin Dynamics Slowdown near the Antiferromagnetic Critical Point in Atomically Thin FePS 3. Nano Lett 2021; 21:5045-5052. [PMID: 34106709 DOI: 10.1021/acs.nanolett.1c00870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two-dimensional (2D) magnetic materials have attracted much recent interest with unique properties emerging at the few-layer limit. Beyond the reported impacts on the static magnetic properties, the effects of reducing the dimensionality on the magnetization dynamics are also of fundamental interest and importance for 2D device development. In this report, we investigate the spin dynamics in atomically thin antiferromagnetic FePS3 of varying layer numbers using ultrafast pump-probe spectroscopy. Following the absorption of an optical pump pulse, the time evolution of the antiferromagnetic order parameter is probed by magnetic linear birefringence. We observe a strong divergence in the demagnetization time near the Néel temperature. The divergence can be characterized by a power-law dependence on the reduced temperature, with an exponent decreasing with sample thickness. We compare our results to expectations from critical slowing down and a two-temperature model involving spins and phonons and discuss the possible relevance of spin-substrate phonon interactions.
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Affiliation(s)
- Xiao-Xiao Zhang
- Department of Physics, University of Florida, Gainesville, Florida 32611, United States
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14850, United States
| | - Shengwei Jiang
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14850, United States
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jinhwan Lee
- Mechanical Engineering, Sungkyunkwan University, 2066 Seoburo Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Changgu Lee
- Mechanical Engineering, Sungkyunkwan University, 2066 Seoburo Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Kin Fai Mak
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14850, United States
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14850, United States
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14850, United States
| | - Jie Shan
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14850, United States
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14850, United States
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14850, United States
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Matsuoka H, Barnes SE, Ieda J, Maekawa S, Bahramy MS, Saika BK, Takeda Y, Wadati H, Wang Y, Yoshida S, Ishizaka K, Iwasa Y, Nakano M. Spin-Orbit-Induced Ising Ferromagnetism at a van der Waals Interface. Nano Lett 2021; 21:1807-1814. [PMID: 33538606 DOI: 10.1021/acs.nanolett.0c04851] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Magnetocrystalline anisotropy, a key ingredient for establishing long-range order in a magnetic material down to the two-dimensional (2D) limit, is generally associated with spin-orbit interaction (SOI) involving a finite orbital angular momentum. Here we report strong out-of-plane magnetic anisotropy without orbital angular momentum, emerging at the interface between two different van der Waals (vdW) materials, an archetypal metallic vdW material NbSe2 possessing Zeeman-type SOI and an isotropic vdW ferromagnet V5Se8. We found that the Zeeman SOI in NbSe2 induces robust out-of-plane magnetic anisotropy in V5Se8 down to the 2D limit with a more than 2-fold enhancement of the transition temperature. We propose a simple model that takes into account the energy gain in NbSe2 in contact with a ferromagnet, which naturally explains our observations. Our results demonstrate a conceptually new magnetic proximity effect at the vdW interface, expanding the horizons of emergent phenomena achievable in vdW heterostructures.
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Affiliation(s)
- Hideki Matsuoka
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
| | | | - Jun'ichi Ieda
- Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan
| | - Sadamichi Maekawa
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Kavli Institute for Theoretical Sciences (KITS), University of Chinese Academy of Sciences, Beijing 100190, China
| | - Mohammad Saeed Bahramy
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
| | - Bruno Kenichi Saika
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
| | - Yukiharu Takeda
- Materials Sciences Research Center, Japan Atomic Energy Agency, Hyogo 679-5148, Japan
| | - Hiroki Wadati
- Graduate School of Material Science, University of Hyogo, Hyogo 678-1297, Japan
| | - Yue Wang
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
| | - Satoshi Yoshida
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
| | - Kyoko Ishizaka
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Yoshihiro Iwasa
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Masaki Nakano
- Quantum-Phase Electronics Center and Department of Applied Physics, the University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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Nakano M, Wang Y, Yoshida S, Matsuoka H, Majima Y, Ikeda K, Hirata Y, Takeda Y, Wadati H, Kohama Y, Ohigashi Y, Sakano M, Ishizaka K, Iwasa Y. Intrinsic 2D Ferromagnetism in V 5Se 8 Epitaxial Thin Films. Nano Lett 2019; 19:8806-8810. [PMID: 31714089 DOI: 10.1021/acs.nanolett.9b03614] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The discoveries of intrinsic ferromagnetism in atomically thin van der Waals crystals have opened a new research field enabling fundamental studies on magnetism at two-dimensional (2D) limit as well as development of magnetic van der Waals heterostructures. Currently, a variety of 2D ferromagnetism has been explored mainly by mechanically exfoliating "originally ferromagnetic (FM)" van der Waals crystals, while a bottom-up approach by thin-film growth technique has demonstrated emergent 2D ferromagnetism in a variety of "originally non-FM" van der Waals materials. Here we demonstrate that V5Se8 epitaxial thin films grown by molecular-beam epitaxy exhibit emergent 2D ferromagnetism with intrinsic spin polarization of the V 3d electrons despite that the bulk counterpart is "originally antiferromagnetic". Moreover, thickness-dependence measurements reveal that this newly developed 2D ferromagnet could be classified as an itinerant 2D Heisenberg ferromagnet with weak magnetic anisotropy, broadening a lineup of 2D magnets to those potentially beneficial for future spintronics applications.
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Affiliation(s)
- Masaki Nakano
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
- RIKEN Center for Emergent Matter Science , Wako 351-0198 , Japan
| | - Yue Wang
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Satoshi Yoshida
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Hideki Matsuoka
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Yuki Majima
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Keisuke Ikeda
- Department of Physics , the University of Tokyo , Tokyo 113-0033 , Japan
| | - Yasuyuki Hirata
- Department of Physics , the University of Tokyo , Tokyo 113-0033 , Japan
- The Institute for Solid State Physics , the University of Tokyo , Kashiwa 227-8581 , Japan
| | - Yukiharu Takeda
- Materials Sciences Research Center , Japan Atomic Energy Agency , Koto City 679-5148 , Hyogo , Japan
| | - Hiroki Wadati
- Department of Physics , the University of Tokyo , Tokyo 113-0033 , Japan
- The Institute for Solid State Physics , the University of Tokyo , Kashiwa 227-8581 , Japan
| | - Yoshimitsu Kohama
- The Institute for Solid State Physics , the University of Tokyo , Kashiwa 227-8581 , Japan
| | - Yuta Ohigashi
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Masato Sakano
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
| | - Kyoko Ishizaka
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
- RIKEN Center for Emergent Matter Science , Wako 351-0198 , Japan
| | - Yoshihiro Iwasa
- Quantum-Phase Electronics Center and Department of Applied Physics , the University of Tokyo , Tokyo 113-8656 , Japan
- RIKEN Center for Emergent Matter Science , Wako 351-0198 , Japan
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15
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Abstract
The recently discovered magnetism of two-dimensional (2D) van der Waals crystals has attracted a lot of attention. Among these materials is CrI3, a magnetic semiconductor, exhibiting transitions between ferromagnetic and antiferromagnetic orderings under the influence of an applied magnetic field. Here, using first-principles methods based on density functional theory, we explore spin-dependent transport in tunnel junctions formed of face-centered cubic Cu(111) electrodes and a CrI3 tunnel barrier. We find about 100% spin polarization of the tunneling current for a ferromagnetically ordered four-monolayer CrI3 and a tunneling magnetoresistance of about 3000% associated with a change of magnetic ordering in CrI3. This behavior is understood in terms of the spin and wave-vector-dependent evanescent states in CrI3, which control the tunneling conductance. We find a sizable charge transfer from Cu to CrI3, which adds new features to the mechanism of spin filtering in CrI3-based tunnel junctions. Our results elucidate the mechanisms of spin filtering in CrI3 tunnel junctions and provide important insights for the design of magnetoresistive devices based on 2D magnetic crystals.
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Affiliation(s)
- Tula R Paudel
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience , University of Nebraska , Lincoln , Nebraska 68588 , United States
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