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Gu Y, Gu Y, Liu F, Ohira-Kawamura S, Murai N, Zhao J. Signatures of Kitaev Interactions in the van der Waals Ferromagnet VI_{3}. PHYSICAL REVIEW LETTERS 2024; 132:246702. [PMID: 38949369 DOI: 10.1103/physrevlett.132.246702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/30/2024] [Accepted: 05/10/2024] [Indexed: 07/02/2024]
Abstract
Materials manifesting the Kitaev model, characterized by bond-dependent interactions on a honeycomb lattice, can host exotic phenomena like quantum spin liquid states and topological magnetic excitations. However, finding such materials remains a formidable challenge. Here, we report high-resolution inelastic neutron scattering measurements performed on VI_{3}, a van der Waals ferromagnetic Mott insulator, covering a wide range of reciprocal space. Our measurements unveil highly anisotropic magnetic excitations in momentum space. Through a comprehensive comparative analysis of various models that incorporate diverse symmetry-allowed magnetic interactions, we find the observed excitations are well captured by a model with a large bond-dependent Kitaev interaction. These results not only help to understand the intriguing properties of VI_{3}, such as the pronounced anomalous thermal Hall effects and strong pressure or structure dependence of magnetism, but also open a new avenue for exploring Kitaev physics.
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Affiliation(s)
- Yiqing Gu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | | | | | | | | | - Jun Zhao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
- Institute of Nanoelectronics and Quantum Computing, Fudan University, Shanghai 200433, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
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De Vita A, Sant R, Polewczyk V, van der Laan G, Brookes NB, Kong T, Cava RJ, Rossi G, Vinai G, Panaccione G. Evidence of Temperature-Dependent Interplay between Spin and Orbital Moment in van der Waals Ferromagnet VI 3. NANO LETTERS 2024; 24:1487-1493. [PMID: 38285518 DOI: 10.1021/acs.nanolett.3c03525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
van der Waals materials provide a versatile toolbox for the emergence of new quantum phenomena and fabrication of functional heterostructures. Among them, the trihalide VI3 stands out for its unique magnetic and structural landscape. Here we investigate the spin and orbital magnetic degrees of freedom in the layered ferromagnet VI3 by means of temperature-dependent X-ray absorption spectroscopy and X-ray magnetic circular and linear dichroism. We detect localized electronic states and reduced magnetic dimensionality, due to electronic correlations. We furthermore provide experimental evidence of (a) an unquenched orbital magnetic moment (up to 0.66(7) μB/V atom) in the ferromagnetic state and (b) an instability of the orbital moment in the proximity of the spin reorientation transition. Our results support a coherent picture where electronic correlations give rise to a strong magnetic anisotropy and a large orbital moment and establish VI3 as a prime candidate for the study of orbital quantum effects.
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Affiliation(s)
- Alessandro De Vita
- Dipartimento di Fisica, Universitá degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Roberto Sant
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble Cedex 9, France
| | - Vincent Polewczyk
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Nicholas B Brookes
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble Cedex 9, France
| | - Tai Kong
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Giorgio Rossi
- Dipartimento di Fisica, Universitá degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Giovanni Vinai
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
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Chen X, Zhang X, Xiang G. Recent advances in two-dimensional intrinsic ferromagnetic materials Fe 3X( X=Ge and Ga)Te 2 and their heterostructures for spintronics. NANOSCALE 2024; 16:527-554. [PMID: 38063022 DOI: 10.1039/d3nr04977a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Owing to their atomic thicknesses, atomically flat surfaces, long-range spin textures and captivating physical properties, two-dimensional (2D) magnetic materials, along with their van der Waals heterostructures (vdWHs), have attracted much interest for the development of next-generation spin-based materials and devices. As an emergent family of intrinsic ferromagnetic materials, Fe3X(X=Ge and Ga)Te2 has become a rising star in the fields of condensed matter physics and materials science owing to their high Curie temperature and large perpendicular magnetic anisotropy. Herein, we aim to comprehensively summarize the recent progress on 2D Fe3X(X=Ge and Ga)Te2 and their vdWHs and provide a panorama of their physical properties and underlying mechanisms. First, an overview of Fe3X(X=Ge and Ga)Te2 is presented in terms of crystalline and electronic structures, distinctive physical properties and preparation methods. Subsequently, the engineering of electronic and spintronic properties of Fe3X(X=Ge and Ga)Te2 by diverse means, including strain, gate voltage, substrate and patterning, is surveyed. Then, the latest advances in spintronic devices based on 2D Fe3X(X=Ge and Ga)Te2 vdWHs are discussed and elucidated in detail, including vdWH devices that exploit the exchange bias effect, magnetoresistance effect, spin-orbit torque effect, magnetic proximity effect and Dzyaloshinskii-Moriya interaction. Finally, the future outlook is given in terms of efficient large-scale fabrication, intriguing physics and important technological applications of 2D Fe3X(X=Ge and Ga)Te2 and their vdWHs. Overall, this study provides an overview to support further studies of emergent 2D Fe3X(X=Ge and Ga)Te2 materials and related vdWH devices for basic science and practical applications.
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Affiliation(s)
- Xia Chen
- College of Physics, Sichuan University, Chengdu 610064, China.
| | - Xi Zhang
- College of Physics, Sichuan University, Chengdu 610064, China.
| | - Gang Xiang
- College of Physics, Sichuan University, Chengdu 610064, China.
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