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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 Z, Yang Y, Ying T, Guo JG. High- Tc Ferromagnetic Semiconductor in Thinned 3D Ising Ferromagnetic Metal Fe 3GaTe 2. NANO LETTERS 2024; 24:993-1000. [PMID: 38190333 DOI: 10.1021/acs.nanolett.3c04462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Emergent phenomena in exfoliated layered transition metal compounds have attracted much attention in the past several years. Especially, pursuing a ferromagnetic insulator is one of the exciting goals for stimulating a high-performance magnetoelectrical device. Here, we report the transition from a metallic to high-Tc semiconductor-like ferromagnet in thinned Fe3GaTe2, accompanied with competition among various magnetic interactions. As evidenced by critical exponents, Fe3GaTe2 is the first layered ferromagnet described by a 3D Ising model coupled with long-range interactions. An extra magnetic phase from competition between ferromagnetism and antiferromagnetism emerges at a low field below Tc. Upon reducing thickness, the Curie temperature (Tc) monotonically decreases from 342 K for bulk to 200 K for 1-3 nm flakes, which is the highest Tc reported as far as we know. Furthermore, a semiconductor-like behavior has been observed in such 1-3 nm flakes. Our results highlight the importance of Fe3GaTe2 in searching for ferromagnetic insulators, which may benefit spintronic device fabrication.
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Affiliation(s)
- Zhaoxu Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuxin Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- College of Materials Sciences and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianping Ying
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jian-Gang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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Wu F, Gibertini M, Watanabe K, Taniguchi T, Gutiérrez-Lezama I, Ubrig N, Morpurgo AF. Magnetism-Induced Band-Edge Shift as the Mechanism for Magnetoconductance in CrPS 4 Transistors. NANO LETTERS 2023; 23:8140-8145. [PMID: 37610296 DOI: 10.1021/acs.nanolett.3c02274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Transistors realized on the 2D antiferromagnetic semiconductor CrPS4 exhibit large magnetoconductance due to magnetic-field-induced changes in the magnetic state. The microscopic mechanism coupling the conductance and magnetic state is not understood. We identify it by analyzing the evolution of the parameters determining the transistor behavior─carrier mobility and threshold voltage─with temperature and magnetic field. For temperatures T near the Néel temperature TN, the magnetoconductance originates from a mobility increase due to the applied magnetic field that reduces spin fluctuation induced disorder. For T ≪ TN, instead, what changes is the threshold voltage, so that increasing the field at fixed gate voltage increases the density of accumulated electrons. The phenomenon is explained by a conduction band-edge shift correctly predicted by the ab initio calculations. Our results demonstrate that the band structure of CrPS4 depends on its magnetic state and reveal a mechanism for magnetoconductance that had not been identified earlier.
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Affiliation(s)
- Fan Wu
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Marco Gibertini
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, University of Modena and Reggio Emilia, IT-41125 Modena, Italy
- Centro S3, CNR Istituto Nanoscienze, IT-41125 Modena, Italy
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Ignacio Gutiérrez-Lezama
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Nicolas Ubrig
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Alberto F Morpurgo
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland
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Wu F, Gibertini M, Watanabe K, Taniguchi T, Gutiérrez-Lezama I, Ubrig N, Morpurgo AF. Gate-Controlled Magnetotransport and Electrostatic Modulation of Magnetism in 2D Magnetic Semiconductor CrPS 4. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2211653. [PMID: 37098224 DOI: 10.1002/adma.202211653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/30/2023] [Indexed: 06/13/2023]
Abstract
Using field-effect transistors (FETs) to explore atomically thin magnetic semiconductors with transport measurements is difficult, because the very narrow bands of most 2D magnetic semiconductors cause carrier localization, preventing transistor operation. Here, it is shown that exfoliated layers of CrPS4 -a 2D layered antiferromagnetic semiconductor whose bandwidth approaches 1 eV-allow the realization of FETs that operate properly down to cryogenic temperature. Using these devices, conductance measurements as a function of temperature and magnetic field are performed to determine the full magnetic phase diagram, which includes a spin-flop and a spin-flip phase. The magnetoconductance, which depends strongly on gate voltage, is determined. reaching values as high as 5000% near the threshold for electron conduction. The gate voltage also allows the magnetic states to be tuned, despite the relatively large thickness of the CrPS4 multilayers employed in the study. The results show the need to employ 2D magnetic semiconductors with sufficiently large bandwidth to realize properly functioning transistors, and identify a candidate material to realize a fully gate-tunable half-metallic conductor.
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Affiliation(s)
- Fan Wu
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
| | - Marco Gibertini
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, University of Modena and Reggio Emilia, Modena, IT-41125, Italy
- Centro S3, CNR Istituto Nanoscienze, Modena, IT-41125, Italy
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Ignacio Gutiérrez-Lezama
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
| | - Nicolas Ubrig
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
| | - Alberto F Morpurgo
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
- Department of Applied Physics, University of Geneva, 24 Quai Ernest Ansermet, Geneva, CH-1211, Switzerland
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Hovančík D, Pospíšil J, Carva K, Sechovský V, Piamonteze C. Large Orbital Magnetic Moment in VI 3. NANO LETTERS 2023; 23:1175-1180. [PMID: 36722374 PMCID: PMC9951247 DOI: 10.1021/acs.nanolett.2c04045] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/10/2023] [Indexed: 06/18/2023]
Abstract
The existence of the V3+-ion orbital moment is an open issue of the nature of magnetism in the van der Waals ferromagnet VI3. The huge magnetocrystalline anisotropy in conjunction with the significantly reduced ordered magnetic moment compared to the spin-only value provides strong but indirect evidence of a large V orbital moment. We used the unique capability of X-ray magnetic circular dichroism to determine the orbital component of the total magnetic moment and provide a direct proof of an exceptionally sizable orbital moment of the V3+ ion in VI3. Our ligand field multiplet simulations of the XMCD spectra in synergy with the results of DFT calculations agree with the existence of two V sites with different orbital occupations and OM magnitudes in the ground state.
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Affiliation(s)
- Dávid Hovančík
- Department
of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121
16Prague 2, Czech Republic
| | - Jiří Pospíšil
- Department
of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121
16Prague 2, Czech Republic
| | - Karel Carva
- Department
of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121
16Prague 2, Czech Republic
| | - Vladimír Sechovský
- Department
of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121
16Prague 2, Czech Republic
| | - Cinthia Piamonteze
- Swiss
Light Source, Paul Scherrer Institut, CH-5232Villigen PSI, Switzerland
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Zhang X, Wang L, Su H, Xia X, Liu C, Lyu B, Lin J, Huang M, Cheng Y, Mei JW, Dai JF. Strain Tunability of Perpendicular Magnetic Anisotropy in van der Waals Ferromagnets VI 3. NANO LETTERS 2022; 22:9891-9899. [PMID: 36519735 DOI: 10.1021/acs.nanolett.2c03156] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Layered ferromagnets with strong magnetic anisotropy energy (MAE) have special applications in nanoscale memory elements in electronic circuits. Here, we report a strain tunability of perpendicular magnetic anisotropy in van der Waals (vdW) ferromagnets VI3 using magnetic circular dichroism measurements. For an unstrained flake, the M-H curve shows a rectangular-shaped hysteresis loop with a large coercivity (1.775 T at 10 K) and remanent magnetization. Furthermore, the coercivity can be enhanced to a maximum of 2.6 T under a 3.8% external in-plane tensile strain. Our DFT calculations show that the increased MAE under strain contributes to the enhancement of coercivity. Meanwhile, the strain tunability on the coercivity of CrI3, with a similar crystal structure, is limited. The main reason is the strong spin-orbit coupling in V3+ in VI6 octahedra in comparison with that in Cr3+. The strain tunability of coercivity in VI3 flakes highlights its potential for integration into vdW heterostructures.
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Affiliation(s)
- Xi Zhang
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering (IBME), Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Le Wang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- International Quantum Academy, Shenzhen 518048, People's Republic of China
| | - Huimin Su
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- International Quantum Academy, Shenzhen 518048, People's Republic of China
| | - Xiuquan Xia
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Cai Liu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- International Quantum Academy, Shenzhen 518048, People's Republic of China
| | - Bingbing Lyu
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Junhao Lin
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Mingyuan Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Jia-Wei Mei
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Jun-Feng Dai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
- International Quantum Academy, Shenzhen 518048, People's Republic of China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, People's Republic of China
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