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Barnowsky T, Curtarolo S, Krasheninnikov AV, Heine T, Friedrich R. Magnetic State Control of Non-van der Waals 2D Materials by Hydrogenation. NANO LETTERS 2024; 24:3874-3881. [PMID: 38446590 PMCID: PMC10996018 DOI: 10.1021/acs.nanolett.3c04777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/15/2024] [Accepted: 02/15/2024] [Indexed: 03/08/2024]
Abstract
Controlling the magnetic state of two-dimensional (2D) materials is crucial for spintronics. By employing data-mining and autonomous density functional theory calculations, we demonstrate the switching of magnetic properties of 2D non-van der Waals materials upon hydrogen passivation. The magnetic configurations are tuned to states with flipped and enhanced moments. For 2D CdTiO3─a diamagnetic compound in the pristine case─we observe an onset of ferromagnetism upon hydrogenation. Further investigation of the magnetization density of the pristine and passivated systems provides a detailed analysis of modified local spin symmetries and the emergence of ferromagnetism. Our results indicate that selective surface passivation is a powerful tool for tailoring magnetic properties of nanomaterials, such as non-vdW 2D compounds.
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Affiliation(s)
- Tom Barnowsky
- Theoretical
Chemistry, Technische Universität
Dresden, Dresden 01062, Germany
- Institute
of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Stefano Curtarolo
- Center
for Extreme Materials, Duke University, Durham, North Carolina 27708, United States
- Materials
Science, Electrical Engineering, and Physics, Duke University, Durham, North Carolina 27708, United States
| | - Arkady V. Krasheninnikov
- Institute
of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Thomas Heine
- Theoretical
Chemistry, Technische Universität
Dresden, Dresden 01062, Germany
- Center
for Advanced Systems Understanding (CASUS), Helmholtz-Zentrum Dresden-Rossendorf, Görlitz 02826, Germany
| | - Rico Friedrich
- Theoretical
Chemistry, Technische Universität
Dresden, Dresden 01062, Germany
- Institute
of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
- Center
for Extreme Materials, Duke University, Durham, North Carolina 27708, United States
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2
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Ni JY, Zheng XM, Wei PT, Liu DY, Zou LJ. Chirality-selective topological magnon phase transition induced by interplay of anisotropic exchange interactions in honeycomb ferromagnet. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:255801. [PMID: 38457834 DOI: 10.1088/1361-648x/ad31c1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 03/08/2024] [Indexed: 03/10/2024]
Abstract
A variety of distinct anisotropic exchange interactions commonly exist in one magnetic material due to complex crystal, magnetic and orbital symmetries. Here we investigate the effects of multiple anisotropic exchange interactions on topological magnon in a honeycomb ferromagnet, and find a chirality-selective topological magnon phase transition induced by a complicated interplay of Dzyaloshinsky-Moriya interaction and pseudo-dipolar interaction, accompanied by the bulk gap close and reopen with chiral inversion. Moreover, this novel topological phase transition involves band inversion at high symmetry pointsKandK', which can be regarded as a pseudo-orbital reversal, i.e. magnon valley degree of freedom, implying a new manipulation corresponding to a sign change of the magnon thermal Hall conductivity. Indeed, it can be realized in 4dor 5dcorrelated materials with both spin-orbit coupling and orbital localized states, such as iridates and ruthenates,etc.This novel regulation may have potential applications on magnon devices and topological magnonics.
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Affiliation(s)
- Jin-Yu Ni
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Xia-Ming Zheng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Peng-Tao Wei
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Da-Yong Liu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Department of Physics, School of Physics and Technology, Nantong University, Nantong 226019, People's Republic of China
| | - Liang-Jian Zou
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
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3
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Rousochatzakis I, Perkins NB, Luo Q, Kee HY. Beyond Kitaev physics in strong spin-orbit coupled magnets. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:026502. [PMID: 38241723 DOI: 10.1088/1361-6633/ad208d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/19/2024] [Indexed: 01/21/2024]
Abstract
We review the recent advances and current challenges in the field of strong spin-orbit coupled Kitaev materials, with a particular emphasis on the physics beyond the exactly-solvable Kitaev spin liquid point. To this end, we present a comprehensive overview of the key exchange interactions in candidate materials with a specific focus on systems featuring effectiveJeff=1/2magnetic moments. This includes, but not limited to,5d5iridates,4d5ruthenates and3d7cobaltates. Our exploration covers the microscopic origins of these interactions, along with a systematic attempt to map out the most intriguing correlated regimes of the multi-dimensional parameter space. Our approach is guided by robust symmetry and duality transformations as well as insights from a wide spectrum of analytical and numerical studies. We also survey higher spin Kitaev models and recent exciting results on quasi-one-dimensional models and discuss their relevance to higher-dimensional models. Finally, we highlight some of the key questions in the field as well as future directions.
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Affiliation(s)
| | - Natalia B Perkins
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, United States of America
- Technical University of Munich, Munich, Germany
- Institute for Advanced Study, D-85748 Garching, Germany
| | - Qiang Luo
- College of Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People's Republic of China
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
| | - Hae-Young Kee
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Canadian Institute for Advanced Research, CIFAR Program in Quantum Materials, Toronto, Ontario M5G 1M1, Canada
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4
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Dos Santos Dias M, Biniskos N, Dos Santos FJ, Schmalzl K, Persson J, Bourdarot F, Marzari N, Blügel S, Brückel T, Lounis S. Topological magnons driven by the Dzyaloshinskii-Moriya interaction in the centrosymmetric ferromagnet Mn 5Ge 3. Nat Commun 2023; 14:7321. [PMID: 37951946 PMCID: PMC10640582 DOI: 10.1038/s41467-023-43042-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023] Open
Abstract
The phase of the quantum-mechanical wave function can encode a topological structure with wide-ranging physical consequences, such as anomalous transport effects and the existence of edge states robust against perturbations. While this has been exhaustively demonstrated for electrons, properties associated with the elementary quasiparticles in magnetic materials are still underexplored. Here, we show theoretically and via inelastic neutron scattering experiments that the bulk ferromagnet Mn5Ge3 hosts gapped topological Dirac magnons. Although inversion symmetry prohibits a net Dzyaloshinskii-Moriya interaction in the unit cell, it is locally allowed and is responsible for the gap opening in the magnon spectrum. This gap is predicted and experimentally verified to close by rotating the magnetization away from the c-axis with an applied magnetic field. Hence, Mn5Ge3 realizes a gapped Dirac magnon material in three dimensions. Its tunability by chemical doping or by thin film nanostructuring defines an exciting new platform to explore and design topological magnons. More generally, our experimental route to verify and control the topological character of the magnons is applicable to bulk centrosymmetric hexagonal materials, which calls for systematic investigation.
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Affiliation(s)
- M Dos Santos Dias
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52425, Jülich, Germany.
- Faculty of Physics, University of Duisburg-Essen and CENIDE, D-47053, Duisburg, Germany.
- Scientific Computing Department, STFC Daresbury Laboratory, Warrington, WA4 4AD, UK.
| | - N Biniskos
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, D-85748, Garching, Germany.
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16, Praha, Czech Republic.
| | - F J Dos Santos
- Laboratory for Materials Simulations, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland.
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
| | - K Schmalzl
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at ILL, 71 Avenue des Martyrs, F-38000, Grenoble, France
| | - J Persson
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI-4), JARA-FIT, D-52425, Jülich, Germany
| | - F Bourdarot
- Université Grenoble Alpes, CEA, IRIG, MEM, MDN, F-38000, Grenoble, France
| | - N Marzari
- Laboratory for Materials Simulations, Paul Scherrer Institut, 5232, Villigen, PSI, Switzerland
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - S Blügel
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52425, Jülich, Germany
| | - T Brückel
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI-4), JARA-FIT, D-52425, Jülich, Germany
| | - S Lounis
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52425, Jülich, Germany
- Faculty of Physics, University of Duisburg-Essen and CENIDE, D-47053, Duisburg, Germany
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5
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Wang K, Ren K, Hou Y, Cheng Y, Zhang G. Magnon-phonon coupling: from fundamental physics to applications. Phys Chem Chem Phys 2023; 25:21802-21815. [PMID: 37581291 DOI: 10.1039/d3cp02683c] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
In recent decades, there are immense applications for bulk and few-layer magnetic insulators in biomedicine, data storage, and signal transfer. In these applications, the interaction between spin and lattice vibration has significant impacts on the device performance. In this article, we systematically review the fundamental physical aspects of magnon-phonon coupling in magnetic insulators. We first introduce the fundamental physics of magnons and magnon-phonon coupling in magnetic insulators and then discuss the influence of magnon-phonon coupling on the properties of magnons and phonons. Finally, a summary is presented, and we also discuss the possible open problems in this field. This article presents the advanced understanding of magnon-phonon coupling in magnetic insulators, which provides new opportunities for improving various possible applications.
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Affiliation(s)
- Ke Wang
- School of Automation, Xi'an University of Posts and Telecommunications, Shaanxi, 710121, China
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, PR China.
| | - Kai Ren
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210042, China
| | - Yinlong Hou
- School of Automation, Xi'an University of Posts and Telecommunications, Shaanxi, 710121, China
| | - Yuan Cheng
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, PR China.
- Department of Materials Science and Engineering, Monash University, VIC 3800, Australia
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, 138632, Singapore.
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6
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Jiang L, Huang C, Liu B, Pan Y, Fan J, Shi D, Ma C, Zhu Y. Same effect of biquadratic exchange interaction and Heisenberg linear interaction in a spin spiral. Phys Chem Chem Phys 2023. [PMID: 37334887 DOI: 10.1039/d3cp00855j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Monolayer (ML) NiCl2 exhibits a strong biquadratic exchange interaction between the first neighboring magnetic atoms (B1), as demonstrated by the spin spiral model in J. Ni et al., Phys. Rev. Lett., 2021, 127, 247204. This interaction is crucial for stabilizing the ferromagnetic collinear order within the ML NiCl2. However, they neither point out the role of B1 nor discuss the dispersion relation from spin orbit coupling (SOC) in the spin spiral. As we have done in this work, these parameters might theoretically potentially be derived directly by fitting the calculated spin spiral dispersion relation. Here, we draw attention to the fact that B1 is equivalent to half of J3 in Heisenberg linear interactions and that the positive B1 partially counteracts the negative J3's impact on the spin spiral to make the ML NiCl2 ferromagnetic. The comparatively small J3 + 1/2B1 from the spin spiral led us to believe that J3 could be substituted by B1, yet it still exists and plays a crucial function in magnetic semiconductors or insulators. The dispersion relation, which we also obtain from SOC, displays weak antiferromagnetic behavior in the spin spiral.
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Affiliation(s)
- Lingzi Jiang
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Can Huang
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Bingjie Liu
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Yanfei Pan
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Jiyu Fan
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Daning Shi
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Chunlan Ma
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Yan Zhu
- College of Physics, Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
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7
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Hou Y, Wei Y, Yang D, Wang K, Ren K, Zhang G. Enhancing the Curie Temperature in Cr 2Ge 2Te 6 via Charge Doping: A First-Principles Study. Molecules 2023; 28:molecules28093893. [PMID: 37175302 PMCID: PMC10180144 DOI: 10.3390/molecules28093893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
In this work, we explore the impacts of charge doping on the magnetism of a Cr2Ge2Te6 monolayer using first-principles calculations. Our results reveal that doping with 0.3 electrons per unit cell can enhance the ferromagnetic exchange constant in a Cr2Ge2Te6 monolayer from 6.874 meV to 10.202 meV, which is accompanied by an increase in the Curie temperature from ~85 K to ~123 K. The enhanced ratio of the Curie temperature is up to 44.96%, even higher than that caused by surface functionalization on monolayer Cr2Ge2Te6, manifesting the effectiveness of charge doping by improving the magnetic stability of 2D magnets. This remarkable enhancement in the ferromagnetic exchange constant and Curie temperature can be attributed to the increase in the magnetic moment on the Te atom, enlarged Cr-Te-Cr bond angle, reduced Cr-Te distance, and the significant increase in super-exchange coupling between Cr and Te atoms. These results demonstrate that charge doping is a promising route to improve the magnetic stability of 2D magnets, which is beneficial to overcome the obstacles in the application of 2D magnets in spintronics.
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Affiliation(s)
- Yinlong Hou
- School of Automation, Xi'an University of Posts & Telecommunications, Xi'an 710121, China
| | - Yu Wei
- School of Automation, Xi'an University of Posts & Telecommunications, Xi'an 710121, China
| | - Dan Yang
- School of Automation, Xi'an University of Posts & Telecommunications, Xi'an 710121, China
| | - Ke Wang
- School of Automation, Xi'an University of Posts & Telecommunications, Xi'an 710121, China
| | - Kai Ren
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing 210042, China
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, Singapore 138632, Singapore
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8
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Ebrahimian A, Dyrdał A, Qaiumzadeh A. Control of magnetic states and spin interactions in bilayer CrCl 3 with strain and electric fields: an ab initio study. Sci Rep 2023; 13:5336. [PMID: 37005471 PMCID: PMC10067849 DOI: 10.1038/s41598-023-32598-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/29/2023] [Indexed: 04/04/2023] Open
Abstract
Using ab initio density functional theory, we demonstrated the possibility of controlling the magnetic ground-state properties of bilayer CrCl[Formula: see text] by means of mechanical strains and electric fields. In principle, we investigated the influence of these two fields on parameters describing the spin Hamiltonian of the system. The obtained results show that biaxial strains change the magnetic ground state between ferromagnetic and antiferromagnetic phases. The mechanical strain also affects the direction and amplitude of the magnetic anisotropy energy (MAE). Importantly, the direction and amplitude of the Dzyaloshinskii-Moriya vectors are also highly tunable under external strain and electric fields. The competition between nearest-neighbor exchange interactions, MAE, and Dzyaloshinskii-Moriya interactions can lead to the stabilization of various exotic spin textures and novel magnetic excitations. The high tunability of magnetic properties by external fields makes bilayer CrCl[Formula: see text] a promising candidate for application in the emerging field of two-dimensional quantum spintronics and magnonics.
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Affiliation(s)
- Ali Ebrahimian
- Department of Mesoscopic Physics, ISQI, Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614, Poznan, Poland
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - Anna Dyrdał
- Department of Mesoscopic Physics, ISQI, Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614, Poznan, Poland
| | - Alireza Qaiumzadeh
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, 7491, Trondheim, Norway.
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9
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Bonini J, Ren S, Vanderbilt D, Stengel M, Dreyer CE, Coh S. Frequency Splitting of Chiral Phonons from Broken Time-Reversal Symmetry in CrI_{3}. PHYSICAL REVIEW LETTERS 2023; 130:086701. [PMID: 36898102 DOI: 10.1103/physrevlett.130.086701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Conventional approaches for lattice dynamics based on static interatomic forces do not fully account for the effects of time-reversal-symmetry breaking in magnetic systems. Recent approaches to rectify this involve incorporating the first-order change in forces with atomic velocities under the assumption of adiabatic separation of electronic and nuclear degrees of freedom. In this Letter, we develop a first-principles method to calculate this velocity-force coupling in extended solids and show via the example of ferromagnetic CrI_{3} that, due to the slow dynamics of the spins in the system, the assumption of adiabatic separation can result in large errors for splittings of zone-center chiral modes. We demonstrate that an accurate description of the lattice dynamics requires treating magnons and phonons on the same footing.
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Affiliation(s)
- John Bonini
- Center for Computational Quantum Physics, Flatiron Institute, 162 5th Avenue, New York, New York 10010, USA
| | - Shang Ren
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08845-0849, USA
| | - David Vanderbilt
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08845-0849, USA
| | - Massimiliano Stengel
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Cyrus E Dreyer
- Center for Computational Quantum Physics, Flatiron Institute, 162 5th Avenue, New York, New York 10010, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA
| | - Sinisa Coh
- Materials Science and Mechanical Engineering, University of California, Riverside, California 92521, USA
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10
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Han X, You JY, Wu S, Li R, Feng YP, Loh KP, Zhao X. Atomically Unveiling an Atlas of Polytypes in Transition-Metal Trihalides. J Am Chem Soc 2023; 145:3624-3635. [PMID: 36735914 DOI: 10.1021/jacs.2c12801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transition-metal trihalides MX3 (M = Cr, Ru; X = Cl, Br, and I) belong to a family of novel two-dimensional (2D) magnets that can exhibit topological magnons and electromagnetic properties, thus affording great promises in next-generation spintronic devices. Rich magnetic ground states observed in the MX3 family are believed to be strongly correlated to the signature Kagome lattice and interlayer van der Waals coupling raised from distinct stacking orders. However, the intrinsic air instability of MX3 makes their direct atomic-scale analysis challenging. Therefore, information on the stacking-registry-dependent magnetism for MX3 remains elusive, which greatly hinders the engineering of desired phases. Here, we report a nondestructive transfer method and successfully realize an intact transfer of bilayer MX3, as evidenced by scanning transmission electron microscopy (STEM). After surveying hundreds of MX3 thin flakes, we provide a full spectrum of stacking orders in MX3 with atomic precision and calculated their associated magnetic ground states, unveiled by combined STEM and density functional theory (DFT). In addition to well-documented phases, we discover a new monoclinic C2/c phase in the antiferromagnetic (AFM) structure widely existing in MX3. Rich stacking polytypes, including C2/c, C2/m, R3̅, P3112, etc., provide rich and distinct magnetic ground states in MX3. Besides, a high density of strain soliton boundaries is consistently found in all MX3, combined with likely inverted structures, allowing AFM to ferromagnetic (FM) transitions in most MX3. Therefore, our study sheds light on the structural basis of diverse magnetic orders in MX3, paving the way for modulating magnetic couplings via stacking engineering.
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Affiliation(s)
- Xiaocang Han
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Jing-Yang You
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551Singapore
| | - Shengqiang Wu
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Runlai Li
- College of Polymer Science & Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu610065, China
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551Singapore
| | - Kian Ping Loh
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, 999077, China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing100871, China
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11
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Wines D, Choudhary K, Tavazza F. Systematic DFT+U and Quantum Monte Carlo Benchmark of Magnetic Two-Dimensional (2D) CrX 3 (X = I, Br, Cl, F). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:10.1021/acs.jpcc.2c06733. [PMID: 36727030 PMCID: PMC9888057 DOI: 10.1021/acs.jpcc.2c06733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The search for two-dimensional (2D) magnetic materials has attracted a great deal of attention because of the experimental synthesis of 2D CrI3, which has a measured Curie temperature of 45 K. Often times, these monolayers have a higher degree of electron correlation and require more sophisticated methods beyond density functional theory (DFT). Diffusion Monte Carlo (DMC) is a correlated electronic structure method that has been demonstrated to be successful for calculating the electronic and magnetic properties of a wide variety of 2D and bulk systems, since it has a weaker dependence on the Hubbard parameter (U) and density functional. In this study, we designed a workflow that combines DFT +U and DMC in order to treat 2D correlated magnetic systems. We chose monolayer CrX3 (X = I, Br, Cl, F), with a stronger focus on CrI3 and CrBr3, as a case study due to the fact that they have been experimentally realized and have a finite critical temperature. With this DFT+U and DMC workflow and the analytical method of Torelli and Olsen, we estimated a maximum value of 43.56 K for the Tc of CrI3 and 20.78 K for the Tc of CrBr3, in addition to analyzing the spin densities and magnetic properties with DMC and DFT+U. We expect that running this workflow for a well-known material class will aid in the future discovery and characterization of lesser known and more complex correlated 2D magnetic materials.
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Affiliation(s)
- Daniel Wines
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
| | - Kamal Choudhary
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States; Theiss Research, La Jolla, California 92037, United States
| | - Francesca Tavazza
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
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12
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Ishizuka H, Sato M. Large Photogalvanic Spin Current by Magnetic Resonance in Bilayer Cr Trihalides. PHYSICAL REVIEW LETTERS 2022; 129:107201. [PMID: 36112457 DOI: 10.1103/physrevlett.129.107201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/08/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
Spin current is a key to realizing various phenomena and functionalities related to spintronics. Recently, the possibility of generating spin current through a photogalvanic effect of magnons was pointed out theoretically. However, neither a candidate material nor a general formula for calculating the photogalvanic spin current in materials is known so far. In this Letter, we develop a general formula for the photogalvanic spin current through a magnetic resonance process. This mechanism involves a one-magnon excitation process in contrast to the two-particle processes studied in earlier works. Using the formula, we show that GHz and THz waves create a large photogalvanic spin current in the antiferromagnetic phase of bilayer CrI_{3} and CrBr_{3}. The large spin current arises from an optical process involving two magnon bands, which is a contribution unknown to date. This spin current appears only in the antiferromagnetic ordered phase and is reversible by controlling the order parameter. These results open a route to material design for the photogalvanic effect of magnetic excitations.
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Affiliation(s)
- Hiroaki Ishizuka
- Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo, 152-8551, Japan
| | - Masahiro Sato
- Department of Physics, Ibaraki University, Mito, Ibaraki 310-8512, Japan
- Department of Physics, Chiba University, Chiba 263-8522, Japan
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13
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Coherent helicity-dependent spin-phonon oscillations in the ferromagnetic van der Waals crystal CrI 3. Nat Commun 2022; 13:4473. [PMID: 35918314 PMCID: PMC9345964 DOI: 10.1038/s41467-022-31786-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 07/04/2022] [Indexed: 11/08/2022] Open
Abstract
The discovery of two-dimensional systems hosting intrinsic magnetic order represents a seminal addition to the rich landscape of van der Waals materials. CrI3 is an archetypal example, where the interdependence of structure and magnetism, along with strong light-matter interactions, provides a new platform to explore the optical control of magnetic and vibrational degrees of freedom at the nanoscale. However, the nature of magneto-structural coupling on its intrinsic ultrafast timescale remains a crucial open question. Here, we probe magnetic and vibrational dynamics in bulk CrI3 using ultrafast optical spectroscopy, revealing spin-flip scattering-driven demagnetization and strong transient exchange-mediated interactions between lattice vibrations and spin oscillations. The latter yields a coherent spin-coupled phonon mode that is highly sensitive to the driving pulse's helicity in the magnetically ordered phase. Our results elucidate the nature of ultrafast spin-lattice coupling in CrI3 and highlight its potential for applications requiring high-speed control of magnetism at the nanoscale.
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14
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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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15
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Staros D, Hu G, Tiihonen J, Nanguneri R, Krogel J, Bennett MC, Heinonen O, Ganesh P, Rubenstein B. A combined first principles study of the structural, magnetic, and phonon properties of monolayer CrI 3. J Chem Phys 2022; 156:014707. [PMID: 34998345 DOI: 10.1063/5.0074848] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The first magnetic 2D material discovered, monolayer (ML) CrI3, is particularly fascinating due to its ground state ferromagnetism. However, because ML materials are difficult to probe experimentally, much remains unresolved about ML CrI3's structural, electronic, and magnetic properties. Here, we leverage Density Functional Theory (DFT) and high-accuracy Diffusion Monte Carlo (DMC) simulations to predict lattice parameters, magnetic moments, and spin-phonon and spin-lattice coupling of ML CrI3. We exploit a recently developed surrogate Hessian DMC line search technique to determine CrI3's ML geometry with DMC accuracy, yielding lattice parameters in good agreement with recently published STM measurements-an accomplishment given the ∼10% variability in previous DFT-derived estimates depending upon the functional. Strikingly, we find that previous DFT predictions of ML CrI3's magnetic spin moments are correct on average across a unit cell but miss critical local spatial fluctuations in the spin density revealed by more accurate DMC. DMC predicts that magnetic moments in ML CrI3 are 3.62 μB per chromium and -0.145 μB per iodine, both larger than previous DFT predictions. The large disparate moments together with the large spin-orbit coupling of CrI3's I-p orbital suggest a ligand superexchange-dominated magnetic anisotropy in ML CrI3, corroborating recent observations of magnons in its 2D limit. We also find that ML CrI3 exhibits a substantial spin-phonon coupling of ∼3.32 cm-1. Our work, thus, establishes many of ML CrI3's key properties, while also continuing to demonstrate the pivotal role that DMC can assume in the study of magnetic and other 2D materials.
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Affiliation(s)
- Daniel Staros
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Guoxiang Hu
- Department of Chemistry and Biochemistry, Queens College, City University of New York, Flushing, New York 11367, USA
| | - Juha Tiihonen
- Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Ravindra Nanguneri
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Jaron Krogel
- Material Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - M Chandler Bennett
- Material Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Olle Heinonen
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Brenda Rubenstein
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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16
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Ni JY, Li XY, Amoroso D, He X, Feng JS, Kan EJ, Picozzi S, Xiang HJ. Giant Biquadratic Exchange in 2D Magnets and Its Role in Stabilizing Ferromagnetism of NiCl_{2} Monolayers. PHYSICAL REVIEW LETTERS 2021; 127:247204. [PMID: 34951786 DOI: 10.1103/physrevlett.127.247204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/29/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) magnets provide an ideal platform for exploring, on the fundamental side, new microscopic mechanisms and for developing, on the technological side, ultracompact spintronic applications. So far, bilinear spin Hamiltonians have been commonly adopted to investigate the magnetic properties of 2D magnets, neglecting higher order magnetic interactions. However, we here provide quantitative evidence of giant biquadratic exchange interactions in monolayer NiX_{2} (X=Cl, Br and I), by combining first-principles calculations and the newly developed machine learning method for constructing Hamiltonian. Interestingly, we show that the ferromagnetic ground state within NiCl_{2} single layers cannot be explained by means of the bilinear Heisenberg Hamiltonian; rather, the nearest-neighbor biquadratic interaction is found to be crucial. Furthermore, using a three-orbitals Hubbard model, we propose that the giant biquadratic exchange interaction originates from large hopping between unoccupied and occupied orbitals on neighboring magnetic ions. On a general framework, our work suggests biquadratic exchange interactions to be important in 2D magnets with edge-shared octahedra.
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Affiliation(s)
- J Y Ni
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- Shanghai Qi Zhi Institution, Shanghai 200030, People's Republic of China
| | - X Y Li
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- Shanghai Qi Zhi Institution, Shanghai 200030, People's Republic of China
| | - D Amoroso
- Consiglio Nazionale delle Ricerche CNR-SPIN Via dei Vestini 31, Chieti 66100, Italy
| | - X He
- Catalan Institude of Nanoscience and Nanotechnology (ICN2), CSIC, BIST, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - J S Feng
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- School of Physics and Materials Engineering, Hefei Normal University, Hefei 230601, People's Republic of China
| | - E J Kan
- Department of Applied Physics and Institution of Energy and Microstructure, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, People's Republic of China
| | - S Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN Via dei Vestini 31, Chieti 66100, Italy
| | - H J Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- Shanghai Qi Zhi Institution, Shanghai 200030, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
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17
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Zhang H, Xu C, Carnahan C, Sretenovic M, Suri N, Xiao D, Ke X. Anomalous Thermal Hall Effect in an Insulating van der Waals Magnet. PHYSICAL REVIEW LETTERS 2021; 127:247202. [PMID: 34951793 DOI: 10.1103/physrevlett.127.247202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/12/2021] [Accepted: 11/10/2021] [Indexed: 06/14/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) magnets have been a fertile playground for the discovery and exploration of physical phenomena and new physics. In this Letter, we report the observation of an anomalous thermal Hall effect (THE) with κ_{xy}∼1×10^{-2} W K^{-1} m^{-1} in an insulating van der Waals ferromagnet VI_{3}. The thermal Hall signal persists in the absence of an external magnetic field and flips sign upon the switching of the magnetization. In combination with theoretical calculations, we show that VI_{3} exhibits a dual nature of the THE, i.e., dominated by topological magnons hosted by the ferromagnetic honeycomb lattice at higher temperatures and by phonons induced by the magnon-phonon coupling at lower temperatures. Our results not only position VI_{3} as the first ferromagnetic system to investigate both anomalous magnon and phonon THEs, but also render it as a potential platform for spintronics-magnonics applications.
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Affiliation(s)
- Heda Zhang
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Chunqiang Xu
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
- School of Physics Southeast University, Nanjing 211189, China
| | - Caitlin Carnahan
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Milos Sretenovic
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
| | - Nishchay Suri
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Xianglin Ke
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA
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18
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Mai TT, Garrity KF, McCreary A, Argo J, Simpson JR, Doan-Nguyen V, Aguilar RV, Walker ARH. Magnon-phonon hybridization in 2D antiferromagnet MnPSe 3. SCIENCE ADVANCES 2021; 7:eabj3106. [PMID: 34714675 PMCID: PMC8555890 DOI: 10.1126/sciadv.abj3106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Magnetic excitations in van der Waals (vdW) materials, especially in the two-dimensional (2D) limit, are an exciting research topic from both the fundamental and applied perspectives. Using temperature-dependent, magneto-Raman spectroscopy, we identify the hybridization of two-magnon excitations with two phonons in manganese phosphorus triselenide (MnPSe3), a magnetic vdW material that hosts in-plane antiferromagnetism. Results from first-principles calculations of the phonon and magnon spectra further support our identification. The Raman spectra’s rich temperature dependence through the magnetic transition displays an avoided crossing behavior in the phonons’ frequency and a concurrent decrease in their lifetimes. We construct a model based on the interaction between a discrete level and a continuum that reproduces these observations. Our results imply a strong hybridization between each phonon and a two-magnon continuum. This work demonstrates that the magnon-phonon interactions can be observed directly in Raman scattering and provides deep insight into these interactions in 2D magnetic materials.
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Affiliation(s)
- Thuc T. Mai
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, NIST, Gaithersburg, MD 20899, USA
- Corresponding author. (T.T.M.); (K.F.G.); (A.R.H.W.)
| | - Kevin F. Garrity
- Materials Measurement Science Division, Materials Measurement Laboratory, NIST, Gaithersburg, MD 20899, USA
- Corresponding author. (T.T.M.); (K.F.G.); (A.R.H.W.)
| | - Amber McCreary
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, NIST, Gaithersburg, MD 20899, USA
| | - Joshua Argo
- Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210, USA
| | - Jeffrey R. Simpson
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, NIST, Gaithersburg, MD 20899, USA
- Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252, USA
| | - Vicky Doan-Nguyen
- Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210, USA
- Center for Emergent Materials, Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Rolando Valdés Aguilar
- Center for Emergent Materials, Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Angela R. Hight Walker
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, NIST, Gaithersburg, MD 20899, USA
- Corresponding author. (T.T.M.); (K.F.G.); (A.R.H.W.)
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19
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Olsen T. Unified Treatment of Magnons and Excitons in Monolayer CrI_{3} from Many-Body Perturbation Theory. PHYSICAL REVIEW LETTERS 2021; 127:166402. [PMID: 34723581 DOI: 10.1103/physrevlett.127.166402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
We present first principles calculations of the two-particle excitation spectrum of CrI_{3} using many-body perturbation theory including spin-orbit coupling. Specifically, we solve the Bethe-Salpeter equation, which is equivalent to summing up all ladder diagrams with static screening, and it is shown that excitons as well as magnons can be extracted seamlessly from the calculations. The resulting optical absorption spectrum as well as the magnon dispersion agree very well with recent measurements, and we extract the amplitude for optical excitation of magnons resulting from spin-orbit interactions. Importantly, the results do not rely on any assumptions of the microscopic magnetic interactions such as Dzyaloshinskii-Moriya (DM), Kitaev, or biquadratic interactions, and we obtain a model independent estimate of the gap between acoustic and optical magnons of 0.3 meV. In addition, we resolve the magnon wave function in terms of band transitions and show that the magnon carries a spin that is significantly smaller than ℏ. This highlights the importance of terms that do not commute with S^{z} in any Heisenberg model description.
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Affiliation(s)
- Thomas Olsen
- CAMD, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby Denmark
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20
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Dupont M, Kvashnin YO, Shiranzaei M, Fransson J, Laflorencie N, Kantian A. Monolayer CrCl_{3} as an Ideal Test Bed for the Universality Classes of 2D Magnetism. PHYSICAL REVIEW LETTERS 2021; 127:037204. [PMID: 34328783 DOI: 10.1103/physrevlett.127.037204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
The monolayer halides CrX_{3} (X=Cl, Br, I) attract significant attention for realizing 2D magnets with genuine long-range order (LRO), challenging the Mermin-Wagner theorem. Here, we show that monolayer CrCl_{3} has the unique benefit of exhibiting tunable magnetic anisotropy upon applying a compressive strain. This opens the possibility to use CrCl_{3} for producing and studying both ferromagnetic and antiferromagnetic 2D Ising-type LRO as well as the Berezinskii-Kosterlitz-Thouless (BKT) regime of 2D magnetism with quasi-LRO. Using state-of-the-art density functional theory, we explain how realistic compressive strain could be used to tune the monolayer's magnetic properties so that it could exhibit any of these phases. Building on large-scale quantum Monte Carlo simulations, we compute the phase diagram of strained CrCl_{3}, as well as the magnon spectrum with spin-wave theory. Our results highlight the eminent suitability of monolayer CrCl_{3} to achieve very high BKT transition temperatures, around 50 K, due to their singular dependence on the weak easy-plane anisotropy of the material.
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Affiliation(s)
- M Dupont
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Y O Kvashnin
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - M Shiranzaei
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - J Fransson
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - N Laflorencie
- Laboratoire de Physique Théorique, IRSAMC, Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - A Kantian
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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21
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Shu Z, Kong T. Spin stiffness of chromium-based van der Waals ferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:195803. [PMID: 33556923 DOI: 10.1088/1361-648x/abe44d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Low temperature magnetization of CrI3, CrSiTe3and CrGeTe3single crystals were systematically studied. Based on the temperature dependence of extrapolated spontaneous magnetization from magnetic isotherms measured at different temperatures, the spin stiffness constant (D) and spin excitation gap (Δ) were extracted according to Bloch's law. For spin stiffness,Dis estimated to be 27 ± 6 meV Å2, 20 ± 3 meV Å2and 38 ± 7 meV Å2for CrI3, CrSiTe3and CrGeTe3respectively. Spin excitation gaps determined via Bloch's formulation have larger error bars yielding 0.59 ± 0.34 meV (CrI3), 0.37 ± 0.22 meV (CrSiTe3) and 0.28 ± 0.19 meV (CrGeTe3). Among all three studied compounds, larger spin stiffness value leads to higher ferromagnetic transition temperature.
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Affiliation(s)
- Zhixue Shu
- Department of Physics, University of Arizona, Tucson, AZ 85721, United States of America
| | - Tai Kong
- Department of Physics, University of Arizona, Tucson, AZ 85721, United States of America
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22
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Lei C, Chittari BL, Nomura K, Banerjee N, Jung J, MacDonald AH. Magnetoelectric Response of Antiferromagnetic CrI 3 Bilayers. NANO LETTERS 2021; 21:1948-1954. [PMID: 33600723 DOI: 10.1021/acs.nanolett.0c04242] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We predict that layer antiferromagnetic bilayers formed from van der Waals (vdW) materials with weak interlayer versus intralayer exchange coupling have strong magnetoelectric response that can be detected in dual-gated devices where internal displacement fields and carrier densities can be varied independently. We illustrate this strong temperature-dependent magnetoelectric response in bilayer CrI3 at charge neutrality by calculating the gate voltage-dependent total magnetization through Monte Carlo simulations and mean-field solutions of the anisotropic Heisenberg model informed from density functional theory and experimental data and present a simple model for electrical control of magnetism by electrostatic doping.
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Affiliation(s)
- Chao Lei
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Bheema L Chittari
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Kentaro Nomura
- Institute for Materials Research, Tohoku University, Sendai Aoba-ku 980-8577, Japan
| | - Nepal Banerjee
- Department of Physics, University of Seoul, Seoul 02504, Korea
- Department of Smart Cities, University of Seoul, Seoul 02504, Korea
| | - Jeil Jung
- Department of Physics, University of Seoul, Seoul 02504, Korea
- Department of Smart Cities, University of Seoul, Seoul 02504, Korea
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
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23
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Wahab DA, Augustin M, Valero SM, Kuang W, Jenkins S, Coronado E, Grigorieva IV, Vera-Marun IJ, Navarro-Moratalla E, Evans RFL, Novoselov KS, Santos EJG. Quantum Rescaling, Domain Metastability, and Hybrid Domain-Walls in 2D CrI 3 Magnets. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004138. [PMID: 33346397 DOI: 10.1002/adma.202004138] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/07/2020] [Indexed: 06/12/2023]
Abstract
Higher-order exchange interactions and quantum effects are widely known to play an important role in describing the properties of low-dimensional magnetic compounds. Here, the recently discovered 2D van der Waals (vdW) CrI3 is identified as a quantum non-Heisenberg material with properties far beyond an Ising magnet as initially assumed. It is found that biquadratic exchange interactions are essential to quantitatively describe the magnetism of CrI3 but quantum rescaling corrections are required to reproduce its thermal properties. The quantum nature of the heat bath represented by discrete electron-spin and phonon-spin scattering processes induces the formation of spin fluctuations in the low-temperature regime. These fluctuations induce the formation of metastable magnetic domains evolving into a single macroscopic magnetization or even a monodomain over surface areas of a few micrometers. Such domains display hybrid characteristics of Néel and Bloch types with a narrow domain wall width in the range of 3-5 nm. Similar behavior is expected for the majority of 2D vdW magnets where higher-order exchange interactions are appreciable.
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Affiliation(s)
- Dina Abdul Wahab
- School of Mathematics and Physics, Queen's University, Belfast, BT7 1NN, UK
| | - Mathias Augustin
- School of Mathematics and Physics, Queen's University, Belfast, BT7 1NN, UK
| | - Samuel Manas Valero
- Instituto de Ciencia Molecular, Universidad de Valencia, Calle Catedrático José Beltrán 2, 46980, Paterna, Spain
| | - Wenjun Kuang
- School of Physics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Sarah Jenkins
- Department of Physics, The University of York, York, YO10 5DD, UK
| | - Eugenio Coronado
- Instituto de Ciencia Molecular, Universidad de Valencia, Calle Catedrático José Beltrán 2, 46980, Paterna, Spain
| | - Irina V Grigorieva
- School of Physics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Ivan J Vera-Marun
- School of Physics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Efrén Navarro-Moratalla
- Instituto de Ciencia Molecular, Universidad de Valencia, Calle Catedrático José Beltrán 2, 46980, Paterna, Spain
| | | | - Kostya S Novoselov
- School of Physics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
- Department of Material Science & Engineering, National University of Singapore, Block EA, 9 Engineering Drive 1 117575, Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing, 400714, China
| | - Elton J G Santos
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
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24
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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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25
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Shao YC, Karki B, Huang W, Feng X, Sumanasekera G, Guo JH, Chuang YD, Freelon B. Spectroscopic Determination of Key Energy Scales for the Base Hamiltonian of Chromium Trihalides. J Phys Chem Lett 2021; 12:724-731. [PMID: 33400873 DOI: 10.1021/acs.jpclett.0c03476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The van der Waals (vdW) chromium trihalides (CrX3) exhibit field-tunable, two-dimensional magnetic orders that vary with the halogen species and the number of layers. Their magnetic ground states with proximity in energies are sensitive to the degree of ligand-metal (p-d) hybridization and relevant modulations in the Cr d-orbital interactions. We use soft X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectroscopy at Cr L-edge along with the atomic multiplet simulations to determine the key energy scales such as the crystal field 10 Dq and interorbital Coulomb interactions under different ligand metal charge transfer (LMCT) in CrX3 (X= Cl, Br, and I). Through this systematic study, we show that our approach compared to the literature has yielded a set of more reliably determined parameters for establishing a base Hamiltonian for CrX3.
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Affiliation(s)
- Y C Shao
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics, University of Houston, Houston, Texas 77204, United States
| | - B Karki
- Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, United States
| | - W Huang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and InformationTechnology, Chinese Academy of Sciences, Shanghai 200050, China
| | - X Feng
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - G Sumanasekera
- Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, United States
| | - J-H Guo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Y-D Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - B Freelon
- Department of Physics, University of Houston, Houston, Texas 77204, United States
- Texas Center for Superconductivity, University of Houston, Houston Texas 77204, United States
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26
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Ahmed S, Carl Cui XY, Ding X, Murmu PP, Bao N, Geng X, Xi S, Liu R, Kennedy J, Wu T, Wang L, Suzuki K, Ding J, Chu X, Clastinrusselraj Indirathankam SR, Peng M, Vinu A, Ringer SP, Yi J. Colossal Magnetization and Giant Coercivity in Ion-Implanted (Nb and Co) MoS 2 Crystals. ACS APPLIED MATERIALS & INTERFACES 2020; 12:58140-58148. [PMID: 33375795 DOI: 10.1021/acsami.0c18150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Colossal saturation magnetization and giant coercivity are realized in MoS2 single crystals doped with Nb and/or Co using an ion implantation method. Magnetic measurements have demonstrated that codoping with 2 at % Nb and 4 at % Co invoked a "giant" coercivity, as high as 9 kOe at 100 K. Doping solely with 5 at % Nb induces a "colossal" magnetization of 1800 emu/cm3 at 5 K, which is higher than that of metallic Co. The high magnetization is due to the formation of Nb-rich defect complexes, as confirmed by first-principles calculations. It is proposed that the high coercivity is due to the combined effects of strong directional exchange coupling induced by the Nb and Co doping and pinning effects from defects within the layered structure. This high magnetization mechanism is also applicable to 2D materials with bilayers or few layers of thickness, as indicated by first-principles calculations. Hence, this work opens a potential pathway for the development of 2D high-performance magnetic materials.
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Affiliation(s)
- Sohail Ahmed
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - Xiang-Yuan Carl Cui
- Australian Centre for Microscopy & Microanalysis, and School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Xiang Ding
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
- School of Energy and Power Engineering, Wuhan University of Technology, Wuhan, Hubei 430063, China
| | - Peter Paul Murmu
- National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt 5010, New Zealand
| | - Nina Bao
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore
| | - Xun Geng
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - Shibo Xi
- Institute of Chemical and Engineering Sciences, A*STAR, 1 Pesek Road, Jurong Island, 627833, Singapore
| | - Rong Liu
- SIMS Facility, Office of the Deputy-Vice Chancellor (Research and Development), Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751, Australia
| | - John Kennedy
- National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt 5010, New Zealand
| | - Tom Wu
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - Lan Wang
- School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Kiyonori Suzuki
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Jun Ding
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore
| | - Xueze Chu
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | | | - Mingli Peng
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China
| | - Ajayan Vinu
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Simon Peter Ringer
- Australian Centre for Microscopy & Microanalysis, and School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jiabao Yi
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
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27
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Jin C, Tao Z, Kang K, Watanabe K, Taniguchi T, Mak KF, Shan J. Imaging and control of critical fluctuations in two-dimensional magnets. NATURE MATERIALS 2020; 19:1290-1294. [PMID: 32514091 DOI: 10.1038/s41563-020-0706-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Strong magnetization fluctuations are expected near the thermodynamic critical point of a continuous magnetic phase transition. Such critical fluctuations are highly correlated and in principle can occur at any time and length scales1; they govern critical phenomena and potentially can drive new phases2,3. Although critical phenomena in magnetic materials have been studied using neutron scattering, magnetic a.c. susceptibility and other techniques4-6, direct real-time imaging of critical magnetization fluctuations remains elusive. Here we develop a fast and sensitive magneto-optical imaging microscope to achieve wide-field, real-time monitoring of critical magnetization fluctuations in single-layer ferromagnetic insulator CrBr3. We track the critical phenomena directly from the fluctuation correlations and observe both slowing-down dynamics and enhanced correlation length. Through real-time feedback control of the critical fluctuations, we further achieve switching of magnetic states solely by electrostatic gating. The ability to directly image and control critical fluctuations in 2D magnets opens up exciting opportunities to explore critical phenomena and develop applications in nanoscale engines and information science.
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Affiliation(s)
- Chenhao Jin
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
| | - Zui Tao
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Kaifei Kang
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | | | - Kin Fai Mak
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
| | - Jie Shan
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
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28
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Wang XS, Brataas A, Troncoso RE. Bosonic Bott Index and Disorder-Induced Topological Transitions of Magnons. PHYSICAL REVIEW LETTERS 2020; 125:217202. [PMID: 33274981 DOI: 10.1103/physrevlett.125.217202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
We investigate the role of disorder on the various topological magnonic phases present in deformed honeycomb ferromagnets. To this end, we introduce a bosonic Bott index to characterize the topology of magnon spectra in finite, disordered systems. The consistency between the Bott index and Chern number is numerically established in the clean limit. We demonstrate that topologically protected magnon edge states are robust to moderate disorder and, as anticipated, localized in the strong regime. We predict a disorder-driven topological phase transition, a magnonic analog of the "topological Anderson insulator" in electronic systems, where the disorder is responsible for the emergence of the nontrivial topology. Combining the results for the Bott index and transport properties, we show that bulk-boundary correspondence holds for disordered topological magnons. Our results open the door for research on topological magnonics as well as other bosonic excitations in finite and disordered systems.
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Affiliation(s)
- X S Wang
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Arne Brataas
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Roberto E Troncoso
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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29
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Guan Z, Ni S. Predicted 2D ferromagnetic Janus VSeTe monolayer with high Curie temperature, large valley polarization and magnetic crystal anisotropy. NANOSCALE 2020; 12:22735-22742. [PMID: 33170918 DOI: 10.1039/d0nr04837b] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The development of two-dimensional (2D) intrinsic ferromagnetic semiconductors is urgent in the spintronic field. Motivated by the recent experiments on the successful synthetization of monolayer (ML) Janus transition-metal dichalcogenides (MoSSe) and ferromagnetic (FM) VSe2, a highly stable ML Janus 2H-VSeTe is fabricated by density functional theory and confirmed by a global minimum search. The Janus VSeTe shows a large valley polarization of 158 meV as the space- and time-reversal symmetry is broken. The VSeTe shows FM order with Curie temperature (Tc) of 350 K and a sizable magnetocrystalline anisotropy (MCA) of -8.54 erg cm-2. The high Tc and large valley polarization suggest the 2D Janus VSeTe is a promising magnetic material for potential applications in electronics, spintronics, and valleytronics.
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Affiliation(s)
- Zhaoyong Guan
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, P. R. China.
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30
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Djurdjić Mijin S, Abeykoon AMM, Šolajić A, Milosavljević A, Pešić J, Liu Y, Petrovic C, Popović ZV, Lazarević N. Short-Range Order in VI 3. Inorg Chem 2020; 59:16265-16271. [PMID: 33092339 DOI: 10.1021/acs.inorgchem.0c02060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a detailed investigation of the crystal structure of VI3, a two-dimensional van der Waals material of interest for studies of low-dimensional magnetism. As opposed to the average crystal structure that features R3̅ symmetry of the unit cell, our Raman scattering and X-ray atomic pair distribution function analysis supported by density functional theory calculations point to the coexistence of short-range ordered P3̅1c and long-range ordered R3̅ phases. The highest-intensity peak, A1g3, exhibits a moderate asymmetry that might be traced back to the spin-phonon interactions, as in the case of CrI3.
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Affiliation(s)
- Sanja Djurdjić Mijin
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
| | - A M Milinda Abeykoon
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Andrijana Šolajić
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
| | - Ana Milosavljević
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
| | - Jelena Pešić
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
| | - Yu Liu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Zoran V Popović
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia.,Serbian Academy of Sciences and Arts, Knez Mihailova 35, 11000 Belgrade, Serbia
| | - Nenad Lazarević
- Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
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31
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Siriwardane EMD, Karki P, Lee Loh Y, Çakır D. Engineering magnetic anisotropy and exchange couplings in double transition metal MXenes via surface defects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:035801. [PMID: 33107444 DOI: 10.1088/1361-648x/abba8e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Two-dimensional (2D) materials have been experimentally proven to manifest almost all types of material properties observed in bulk materials. However, 2D magnetism was elusive until recently. In this work, we used an approach that synergistically uses density functional theory, and Monte Carlo methods to investigate the magnetic and electronic properties of magnetic double transition metal MXene alloys (Hf2MnC2O2and Hf2VC2O2) by exploiting realistic surface terminations via creating surface defects including oxygen vacancies and H adatoms. We found that introducing surface oxygen vacancies or hydrogen adatoms is able to modify the electronic structures, magnetic anisotropies, and exchange couplings. Depending on the defect concentration, a ferromagnetic half-metallic state can be realized for both Hf2VC2O2and Hf2MnC2O2. Bare Hf2VC2O2exhibits easy-axis anisotropy, whereas bare Hf2MnC2O2exhibits easy-plane anisotropy; however, defects can change the latter to easy-axis anisotropy, which is preferable for spintronics applications. The considered defects were found to modify the magnetic anisotropy by as much as 300%. Defects also produce an inhomogeneous pattern of exchange couplings, which can further enhance the Curie temperature. In particular, Hf2MnC2O2H0.22was predicted to have a Curie temperature of about 171 K due to a combination of easy-axis anisotropy and a connected network of enhanced exchange couplings. Our calculations suggest a route toward engineering exchange couplings and magnetic anisotropy to improve magnetic properties.
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Affiliation(s)
- Edirisuriya M D Siriwardane
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, United States of America
| | - Pragalv Karki
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, United States of America
| | - Yen Lee Loh
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, United States of America
| | - Deniz Çakır
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, United States of America
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32
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Kundu AK, Liu Y, Petrovic C, Valla T. Valence band electronic structure of the van der Waals ferromagnetic insulators: VI[Formula: see text] and CrI[Formula: see text]. Sci Rep 2020; 10:15602. [PMID: 32973193 PMCID: PMC7515918 DOI: 10.1038/s41598-020-72487-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 08/28/2020] [Indexed: 12/03/2022] Open
Abstract
Ferromagnetic van der Waals (vdW) insulators are of great scientific interest for their promising applications in spintronics. It has been indicated that in the two materials within this class, CrI[Formula: see text] and VI[Formula: see text], the magnetic ground state, the band gap, and the Fermi level could be manipulated by varying the layer thickness, strain or doping. To understand how these factors impact the properties, a detailed understanding of the electronic structure would be required. However, the experimental studies of the electronic structure of these materials are still very sparse. Here, we present the detailed electronic structure of CrI[Formula: see text] and VI[Formula: see text] measured by angle-resolved photoemission spectroscopy (ARPES). Our results show a band-gap of the order of 1 eV, sharply contrasting some theoretical predictions such as Dirac half-metallicity and metallic phases, indicating that the intra-atomic interaction parameter (U) and spin-orbit coupling (SOC) were not properly accounted for in the calculations. We also find significant differences in the electronic properties of these two materials, in spite of similarities in their crystal structure. In CrI[Formula: see text], the valence band maximum is dominated by the I 5p, whereas in VI[Formula: see text] it is dominated by the V 3d derived states. Our results represent valuable input for further improvements in the theoretical modeling of these systems.
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Affiliation(s)
- Asish K. Kundu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA
| | - Yu Liu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA
- Present Address: Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545 USA
| | - C. Petrovic
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA
| | - T. Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 USA
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33
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Soriano D, Katsnelson MI, Fernández-Rossier J. Magnetic Two-Dimensional Chromium Trihalides: A Theoretical Perspective. NANO LETTERS 2020; 20:6225-6234. [PMID: 32787171 DOI: 10.1021/acs.nanolett.0c02381] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The discovery of ferromagnetic order in monolayer two-dimensional (2D) crystals has opened a new venue in the field of 2D materials. Two-dimensional magnets are not only interesting on their own, but their integration in van der Waals heterostructures allows for the observation of new and exotic effects in the ultrathin limit. The family of chromium trihalides, CrI3, CrBr3, and CrCl3, is so far the most studied among magnetic 2D crystals. In this Mini Review, we provide a perspective of the state of the art of the theoretical understanding of magnetic 2D trihalides, most of which will also be relevant for other 2D magnets, such as vanadium trihalides. We discuss both the well-established facts, such as the origin of the magnetic moment and magnetic anisotropy, and address as well open issues such as the nature of the anisotropic spin couplings and the magnitude of the magnon gap. Recent theoretical predictions on Moiré magnets and magnetic skyrmions are also discussed. Finally, we give some prospects about the future interest of these materials and possible device applications.
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Affiliation(s)
- D Soriano
- Institute for Molecules and Materials, Radboud University, NL-6525 AJ Nijmegen, The Netherlands
| | - M I Katsnelson
- Institute for Molecules and Materials, Radboud University, NL-6525 AJ Nijmegen, The Netherlands
| | - J Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory (INL), Avenido Mestre José Veiga, 4715-330 Braga, Portugal
- Departamento de Física Aplicada, Universidad de Alicante, 03690, Alicante, Spain
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Distinct magneto-Raman signatures of spin-flip phase transitions in CrI 3. Nat Commun 2020; 11:3879. [PMID: 32747673 PMCID: PMC7398929 DOI: 10.1038/s41467-020-17320-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 06/19/2020] [Indexed: 11/08/2022] Open
Abstract
The discovery of 2-dimensional (2D) materials, such as CrI3, that retain magnetic ordering at monolayer thickness has resulted in a surge of both pure and applied research in 2D magnetism. Here, we report a magneto-Raman spectroscopy study on multilayered CrI3, focusing on two additional features in the spectra that appear below the magnetic ordering temperature and were previously assigned to high frequency magnons. Instead, we conclude these modes are actually zone-folded phonons. We observe a striking evolution of the Raman spectra with increasing magnetic field applied perpendicular to the atomic layers in which clear, sudden changes in intensities of the modes are attributed to the interlayer ordering changing from antiferromagnetic to ferromagnetic at a critical magnetic field. Our work highlights the sensitivity of the Raman modes to weak interlayer spin ordering in CrI3.
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35
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Zhang XX, Li L, Weber D, Goldberger J, Mak KF, Shan J. Gate-tunable spin waves in antiferromagnetic atomic bilayers. NATURE MATERIALS 2020; 19:838-842. [PMID: 32572203 DOI: 10.1038/s41563-020-0713-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/20/2020] [Indexed: 05/20/2023]
Abstract
Remarkable properties of two-dimensional (2D) layer magnetic materials, which include spin filtering in magnetic tunnel junctions and the gate control of magnetic states, were demonstrated recently1-12. Whereas these studies focused on static properties, dynamic magnetic properties, such as excitation and control of spin waves, remain elusive. Here we investigate spin-wave dynamics in antiferromagnetic CrI3 bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique. Monolayer WSe2 with a strong excitonic resonance was introduced on CrI3 to enhance the optical excitation of spin waves. We identified subterahertz magnetic resonances under an in-plane magnetic field, from which the anisotropy and interlayer exchange fields were determined. We further showed tuning of the antiferromagnetic resonances by tens of gigahertz through electrostatic gating. Our results shed light on magnetic excitations and spin dynamics in 2D magnetic materials, and demonstrate their potential for applications in ultrafast data storage and processing.
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Affiliation(s)
- Xiao-Xiao Zhang
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
- Department of Physics, University of Florida, Gainesville, FL, USA
| | - Lizhong Li
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Daniel Weber
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Joshua Goldberger
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Kin Fai Mak
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
| | - Jie Shan
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA.
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
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36
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Tartaglia TA, Tang JN, Lado JL, Bahrami F, Abramchuk M, McCandless GT, Doyle MC, Burch KS, Ran Y, Chan JY, Tafti F. Accessing new magnetic regimes by tuning the ligand spin-orbit coupling in van der Waals magnets. SCIENCE ADVANCES 2020; 6:eabb9379. [PMID: 32832677 PMCID: PMC7439302 DOI: 10.1126/sciadv.abb9379] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/04/2020] [Indexed: 05/30/2023]
Abstract
Van der Waals (VdW) materials have opened new directions in the study of low dimensional magnetism. A largely unexplored arena is the intrinsic tuning of VdW magnets toward new ground states. Chromium trihalides provided the first such example with a change of interlayer magnetic coupling emerging upon exfoliation. Here, we take a different approach to engineer previously unknown ground states, not by exfoliation, but by tuning the spin-orbit coupling (SOC) of the nonmagnetic ligand atoms (Cl, Br, I). We synthesize a three-halide series, CrCl3 - x - y Br x I y , and map their magnetic properties as a function of Cl, Br, and I content. The resulting triangular phase diagrams unveil a frustrated regime near CrCl3. First-principles calculations confirm that the frustration is driven by a competition between the chromium and halide SOCs. Furthermore, we reveal a field-induced change of interlayer coupling in the bulk of CrCl3 - x - y Br x I y crystals at the same field as in the exfoliation experiments.
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Affiliation(s)
| | - Joseph N. Tang
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Jose L. Lado
- Department of Applied Physics, Aalto University, Espoo, Finland
| | - Faranak Bahrami
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Mykola Abramchuk
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Gregory T. McCandless
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Meaghan C. Doyle
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Kenneth S. Burch
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Ying Ran
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
| | - Julia Y. Chan
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Fazel Tafti
- Department of Physics, Boston College, Chestnut Hill, MA 02467, USA
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37
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De Siena MC, Creutz SE, Regan A, Malinowski P, Jiang Q, Kluherz KT, Zhu G, Lin Z, De Yoreo JJ, Xu X, Chu JH, Gamelin DR. Two-Dimensional van der Waals Nanoplatelets with Robust Ferromagnetism. NANO LETTERS 2020; 20:2100-2106. [PMID: 32031382 DOI: 10.1021/acs.nanolett.0c00102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have synthesized unique colloidal nanoplatelets of the two-dimensional (2D) van der Waals ferromagnet CrI3 and have characterized these nanoplatelets structurally, magnetically, and by magnetic circular dichroism spectroscopy. The CrI3 nanoplatelets have lateral dimensions of ∼25 nm and thicknesses of only ∼4 nm, corresponding to just a few CrI3 monolayers. Magnetic and magneto-optical measurements demonstrate robust 2D ferromagnetic ordering with Curie temperatures similar to bulk CrI3, despite their small size. These data also show magnetization steps akin to those observed in micron-sized few-layer 2D sheets associated with concerted spin-reversal of individual CrI3 layers within few-layer van der Waals stacks. Similar data have also been obtained for CrBr3 and anion-alloyed Cr(I1-xBrx)3 nanoplatelets. These results represent the first example of lateral nanostructures of 2D van der Waals ferromagnets of any composition. The demonstration of robust ferromagnetism at nanometer lateral dimensions opens new doors for miniaturization in spintronics devices based on van der Waals ferromagnets.
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Affiliation(s)
- Michael C De Siena
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Sidney E Creutz
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Annie Regan
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Paul Malinowski
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Qianni Jiang
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Kyle T Kluherz
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Guomin Zhu
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Zhong Lin
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - James J De Yoreo
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, 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
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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38
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Xu C, Feng J, Kawamura M, Yamaji Y, Nahas Y, Prokhorenko S, Qi Y, Xiang H, Bellaiche L. Possible Kitaev Quantum Spin Liquid State in 2D Materials with S=3/2. PHYSICAL REVIEW LETTERS 2020; 124:087205. [PMID: 32167315 DOI: 10.1103/physrevlett.124.087205] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Quantum spin liquids (QSLs) form an extremely unusual magnetic state in which the spins are highly correlated and fluctuate coherently down to the lowest temperatures, but without symmetry breaking and without the formation of any static long-range-ordered magnetism. Such intriguing phenomena are not only of great fundamental relevance in themselves, but also hold promise for quantum computing and quantum information. Among different types of QSLs, the exactly solvable Kitaev model is attracting much attention, with most proposed candidate materials, e.g., RuCl_{3} and Na_{2}IrO_{3}, having an effective S=1/2 spin value. Here, via extensive first-principles-based simulations, we report the investigation of the Kitaev physics and possible Kitaev QSL state in epitaxially strained Cr-based monolayers, such as CrSiTe_{3}, that rather possess a S=3/2 spin value. Our study thus extends the playground of Kitaev physics and QSLs to 3d transition metal compounds.
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Affiliation(s)
- Changsong Xu
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Junsheng Feng
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- School of Physics and Materials Engineering, Hefei Normal University, Hefei 230601, People's Republic of China
| | - Mitsuaki Kawamura
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa-shi, Chiba 277-8581, Japan
| | - Youhei Yamaji
- Department of Applied Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Yang Qi
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
| | - Hongjun Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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39
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Redemann BWY, Scudder MR, Weber D, Wang Y, Windl W, Goldberger JE. Synthesis, structural, and electronic properties of Sr 1−xCa xPdAs. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00284d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
.This work maps out the structural and electronic phase diagram of Sr1-xCaxPdAs, a unique family of layered intermetallic honeycomb phases in which the PdAs layers distort away from ideal hexagonal symmetry.
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Affiliation(s)
| | - Michael R. Scudder
- Department of Chemistry and Biochemistry
- The Ohio State University
- Columbus
- USA
| | - Daniel Weber
- Department of Chemistry and Biochemistry
- The Ohio State University
- Columbus
- USA
| | - Yaxian Wang
- Department of Materials Science and Engineering
- The Ohio State University
- Columbus
- USA
| | - Wolfgang Windl
- Department of Materials Science and Engineering
- The Ohio State University
- Columbus
- USA
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