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Gao FY, Peng X, Cheng X, Viñas Boström E, Kim DS, Jain RK, Vishnu D, Raju K, Sankar R, Lee SF, Sentef MA, Kurumaji T, Li X, Tang P, Rubio A, Baldini E. Giant chiral magnetoelectric oscillations in a van der Waals multiferroic. Nature 2024; 632:273-279. [PMID: 39020169 PMCID: PMC11306099 DOI: 10.1038/s41586-024-07678-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 06/05/2024] [Indexed: 07/19/2024]
Abstract
Helical spin structures are expressions of magnetically induced chirality, entangling the dipolar and magnetic orders in materials1-4. The recent discovery of helical van der Waals multiferroics down to the ultrathin limit raises prospects of large chiral magnetoelectric correlations in two dimensions5,6. However, the exact nature and magnitude of these couplings have remained unknown so far. Here we perform a precision measurement of the dynamical magnetoelectric coupling for an enantiopure domain in an exfoliated van der Waals multiferroic. We evaluate this interaction in resonance with a collective electromagnon mode, capturing the impact of its oscillations on the dipolar and magnetic orders of the material with a suite of ultrafast optical probes. Our data show a giant natural optical activity at terahertz frequencies, characterized by quadrature modulations between the electric polarization and magnetization components. First-principles calculations further show that these chiral couplings originate from the synergy between the non-collinear spin texture and relativistic spin-orbit interactions, resulting in substantial enhancements over lattice-mediated effects. Our findings highlight the potential for intertwined orders to enable unique functionalities in the two-dimensional limit and pave the way for the development of van der Waals magnetoelectric devices operating at terahertz speeds.
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Affiliation(s)
- Frank Y Gao
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, USA
| | - Xinyue Peng
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, USA
| | - Xinle Cheng
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Emil Viñas Boström
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
- Nano-Bio Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco, San Sebastián, Spain
| | - Dong Seob Kim
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, USA
| | - Ravish K Jain
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Deepak Vishnu
- Institute of Physics, Academia Sinica, Taipei, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | | | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Shang-Fan Lee
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Michael A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
- Institute for Theoretical Physics and Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany
| | - Takashi Kurumaji
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA, USA
| | - Xiaoqin Li
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, USA
| | - Peizhe Tang
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
- Nano-Bio Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco, San Sebastián, Spain.
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, USA.
| | - Edoardo Baldini
- Department of Physics and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, USA.
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2
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Castro M, Saéz G, Vergara Apaz P, Allende S, Nunez AS. Toward Fully Multiferroic van der Waals SpinFETs: Basic Design and Quantum Calculations. NANO LETTERS 2024; 24:7911-7918. [PMID: 38889449 DOI: 10.1021/acs.nanolett.4c01146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Manipulating spin transport enhances the functionality of electronic devices, allowing them to surpass physical constraints related to speed and power. For this reason, the use of van der Waals multiferroics at the interface of heterostructures offers promising prospects for developing high-performance devices, enabling the electrical control of spin information. Our work focuses primarily on a mechanism for multiferroicity in two-dimensional van der Waals materials that stems from an interplay between antiferromagnetism and the breaking of inversion symmetry in certain bilayers. We provide evidence for spin-electrical couplings that include manipulating van der Waals multiferroic edges via external voltages and the subsequent control of spin transport including for fully multiferroic spin field-effect transistors.
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Affiliation(s)
- Mario Castro
- Departamento de Física, FCFM, Universidad de Chile, Santiago, 8370448, Chile
- Centro de Nanociencia y Nanotecnología CEDENNA, Santiago, 9170124, Chile
| | - Guidobeth Saéz
- Departamento de Física, FCFM, Universidad de Chile, Santiago, 8370448, Chile
- Centro de Nanociencia y Nanotecnología CEDENNA, Santiago, 9170124, Chile
| | | | - Sebastián Allende
- Centro de Nanociencia y Nanotecnología CEDENNA, Santiago, 9170124, Chile
- Departamento de Física, Universidad de Santiago de Chile, Santiago, 9170124, Chile
| | - Alvaro S Nunez
- Departamento de Física, FCFM, Universidad de Chile, Santiago, 8370448, Chile
- Centro de Nanociencia y Nanotecnología CEDENNA, Santiago, 9170124, Chile
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3
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Aoki S, Dong Y, Wang Z, Huang XSW, Itahashi YM, Ogawa N, Ideue T, Iwasa Y. Giant Modulation of the Second Harmonic Generation by Magnetoelectricity in Two-Dimensional Multiferroic CuCrP 2S 6. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312781. [PMID: 38533684 DOI: 10.1002/adma.202312781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/22/2024] [Indexed: 03/28/2024]
Abstract
Multiferroic materials have attracted considerable attention owing to their unique magnetoelectric or magnetooptical properties. The recent discovery of few-layer van der Waals multiferroic crystals provides a new research direction for controlling the multiferroic properties in the atomic layer limit. However, research on few-layer multiferroic crystals is limited and the effect of thickness-dependent symmetries on those properties is less explored. In this study, the symmetries and magnetoelectric responses of van der Waals multiferroic CuCrP2S6 are investigated by optical second harmonic generation (SHG). Structural and magnetic phase transitions are successfully probed by the temperature-dependent SHG signals, revealing significant changes by applying the magnetic field reflecting the magnetoelectric effect. Moreover, it is found that symmetries and resultant magnetoelectric responses can be modulated by the number of layers. These results offer a new principle of controlling the multiferroicity and indicate that 2D van der Waals multiferroic material is a promising building block for functional nanodevices.
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Affiliation(s)
- Shunta Aoki
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Yu Dong
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Ziqian Wang
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Xiang S W Huang
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Yuki M Itahashi
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoki Ogawa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Toshiya Ideue
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, 277-8581, Japan
| | - Yoshihiro Iwasa
- Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
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4
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Amini M, Fumega AO, González-Herrero H, Vaňo V, Kezilebieke S, Lado JL, Liljeroth P. Atomic-Scale Visualization of Multiferroicity in Monolayer NiI 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311342. [PMID: 38241258 DOI: 10.1002/adma.202311342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/09/2024] [Indexed: 01/21/2024]
Abstract
Progress in layered van der Waals materials has resulted in the discovery of ferromagnetic and ferroelectric materials down to the monolayer limit. Recently, evidence of the first purely 2D multiferroic material was reported in monolayer NiI2. However, probing multiferroicity with scattering-based and optical bulk techniques is challenging on 2D materials, and experiments on the atomic scale are needed to fully characterize the multiferroic order at the monolayer limit. Here, scanning tunneling microscopy (STM) supported by density functional theory (DFT) calculations is used to probe and characterize the multiferroic order in monolayer NiI2. It is demonstrated that the type-II multiferroic order displayed by NiI2, arising from the combination of a magnetic spin spiral order and a strong spin-orbit coupling, allows probing the multiferroic order in the STM experiments. Moreover, the magnetoelectric coupling of NiI2 is directly probed by external electric field manipulation of the multiferroic domains. The findings establish a novel point of view to analyze magnetoelectric effects at the microscopic level, paving the way toward engineering new multiferroic orders in van der Waals materials and their heterostructures.
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Affiliation(s)
- Mohammad Amini
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
| | - Adolfo O Fumega
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
| | - Héctor González-Herrero
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, E-28049, Spain
| | - Viliam Vaňo
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - Shawulienu Kezilebieke
- Department of Physics, Department of Chemistry and Nanoscience Center, University of Jyväskylä, Jyväskylä, FI-40014, Finland
| | - Jose L Lado
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
| | - Peter Liljeroth
- Department of Applied Physics, Aalto University, Aalto, FI-00076, Finland
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5
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Fu Y, Liu Z, Yue S, Zhang K, Wang R, Zhang Z. Optical Second Harmonic Generation of Low-Dimensional Semiconductor Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:662. [PMID: 38668156 PMCID: PMC11054873 DOI: 10.3390/nano14080662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 04/02/2024] [Accepted: 04/07/2024] [Indexed: 04/29/2024]
Abstract
In recent years, the phenomenon of optical second harmonic generation (SHG) has attracted significant attention as a pivotal nonlinear optical effect in research. Notably, in low-dimensional materials (LDMs), SHG detection has become an instrumental tool for elucidating nonlinear optical properties due to their pronounced second-order susceptibility and distinct electronic structure. This review offers an exhaustive overview of the generation process and experimental configurations for SHG in such materials. It underscores the latest advancements in harnessing SHG as a sensitive probe for investigating the nonlinear optical attributes of these materials, with a particular focus on its pivotal role in unveiling electronic structures, bandgap characteristics, and crystal symmetry. By analyzing SHG signals, researchers can glean invaluable insights into the microscopic properties of these materials. Furthermore, this paper delves into the applications of optical SHG in imaging and time-resolved experiments. Finally, future directions and challenges toward the improvement in the NLO in LDMs are discussed to provide an outlook in this rapidly developing field, offering crucial perspectives for the design and optimization of pertinent devices.
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Affiliation(s)
- Yue Fu
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
| | - Zhengyan Liu
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
- School of Integrated Circuits, University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
| | - Song Yue
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
- School of Integrated Circuits, University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
| | - Kunpeng Zhang
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
| | - Ran Wang
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
- School of Integrated Circuits, University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
| | - Zichen Zhang
- Microelectronics Instruments and Equipment R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, 3 Beitucheng West Road, Beijing 100029, China; (Y.F.); (Z.L.); (S.Y.); (K.Z.)
- School of Integrated Circuits, University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Beijing 100049, China
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6
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Wang J, Cheng F, Sun Y, Xu H, Cao L. Stacking engineering in layered homostructures: transitioning from 2D to 3D architectures. Phys Chem Chem Phys 2024; 26:7988-8012. [PMID: 38380525 DOI: 10.1039/d3cp04656g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Artificial materials, characterized by their distinctive properties and customized functionalities, occupy a central role in a wide range of applications including electronics, spintronics, optoelectronics, catalysis, and energy storage. The emergence of atomically thin two-dimensional (2D) materials has driven the creation of artificial heterostructures, harnessing the potential of combining various 2D building blocks with complementary properties through the art of stacking engineering. The promising outcomes achieved for heterostructures have spurred an inquisitive exploration of homostructures, where identical 2D layers are precisely stacked. This perspective primarily focuses on the field of stacking engineering within layered homostructures, where precise control over translational or rotational degrees of freedom between vertically stacked planes or layers is paramount. In particular, we provide an overview of recent advancements in the stacking engineering applied to 2D homostructures. Additionally, we will shed light on research endeavors venturing into three-dimensional (3D) structures, which allow us to proactively address the limitations associated with artificial 2D homostructures. We anticipate that the breakthroughs in stacking engineering in 3D materials will provide valuable insights into the mechanisms governing stacking effects. Such advancements have the potential to unlock the full capability of artificial layered homostructures, propelling the future development of materials, physics, and device applications.
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Affiliation(s)
- Jiamin Wang
- Changchun Institute of Optics, Fine Mechanics & Physics (CIOMP), Chinese Academy of Sciences, Changchun 130033, P. R. China.
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Fang Cheng
- State Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, Nanjing 210023, P. R. China
| | - Yan Sun
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China.
| | - Hai Xu
- Changchun Institute of Optics, Fine Mechanics & Physics (CIOMP), Chinese Academy of Sciences, Changchun 130033, P. R. China.
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Liang Cao
- Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, P. R. China.
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7
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Moradifar P, Liu Y, Shi J, Siukola Thurston ML, Utzat H, van Driel TB, Lindenberg AM, Dionne JA. Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy. Chem Rev 2023. [PMID: 37979189 DOI: 10.1021/acs.chemrev.2c00917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material's detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure-function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials' intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.
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Affiliation(s)
- Parivash Moradifar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Yin Liu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jiaojian Shi
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | | | - Hendrik Utzat
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Tim B van Driel
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Aaron M Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | - Jennifer A Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Stanford University, Stanford, California 94305, United States
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8
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Gao Y, Li S, Zeng XC, Wu M. Exploitation of mixed-valency chemistry for designing a monolayer with double ferroelectricity and triferroic couplings. NANOSCALE 2023; 15:13567-13573. [PMID: 37565465 DOI: 10.1039/d3nr02216a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Mixed-valence compounds possess both intriguing chemical and physical properties such as the intervalence charge transfer band and thus have been excellent model systems for the investigation of fundamental electron- and charge-transfer phenomena. Herein, we show that valence stratification can be a source of symmetry breaking and generating ferroelectricity in two-dimensional (2D) materials. We present ab initio computation evidence of the monolayer Cu2Cl3 structure with Cu ions being stratified into two separated layers of Cu(I) and Cu(II). Chemically, this unique monolayer not only entails lower formation energy than the bulk CuCl + CuCl2, but also enables the swapping of two valences through vertical ferroelectric switching, leading to a hitherto unreported chemical valencing phenomenon. Notably, the Jahn-Teller distortion of the Cu(II) layer results in another source of symmetry breaking and thus in-plane ferroelectricity. Apart from the valence swapping and self-contained double ferroelectricity, the monolayer's ferroelasticity is also coupled with in-plane ferroelectricity, while the monolayer's ferromagnetism is coupled with vertical polarization owing to the distinct magnetization of each Cu(I) and Cu(II) layer, thereby evoking the long-sought 2D triferroicity as well as triferroic couplings.
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Affiliation(s)
- Yaxin Gao
- School of Physics and Mechanical Electrical & Engineering, Institute of Theoretical Physics, Hubei University of Education, Wuhan, Hubei 430205, China.
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Sha Li
- School of Physics and Mechanical Electrical & Engineering, Institute of Theoretical Physics, Hubei University of Education, Wuhan, Hubei 430205, China.
| | - Xiao Cheng Zeng
- Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China.
| | - Menghao Wu
- School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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9
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Li X, Xu C, Liu B, Li X, Bellaiche L, Xiang H. Realistic Spin Model for Multiferroic NiI_{2}. PHYSICAL REVIEW LETTERS 2023; 131:036701. [PMID: 37540870 DOI: 10.1103/physrevlett.131.036701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/11/2023] [Accepted: 06/17/2023] [Indexed: 08/06/2023]
Abstract
A realistic first-principle-based spin Hamiltonian is constructed for the type-II multiferroic NiI_{2}, using a symmetry-adapted cluster expansion method. Besides single ion anisotropy and isotropic Heisenberg terms, this model further includes the Kitaev interaction and a biquadratic term, and can well reproduce striking features of the experimental helical ground state, that are, e.g., a proper screw state, canting of rotation plane, propagation direction, and period. Using this model to build a phase diagram, it is demonstrated that, (i) the in-plane propagation direction of ⟨11[over ¯]0⟩ is determined by the Kitaev interaction, instead of the long-believed exchange frustrations and (ii) the canting of rotation plane is also dominantly determined by Kitaev interaction, rather than interlayer couplings. Furthermore, additional Monte Carlo simulations reveal three equivalent domains and different topological defects. Since the ferroelectricity is induced by spins in type-II multiferroics, our work also implies that Kitaev interaction is closely related to the multiferroicity of NiI_{2}.
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Affiliation(s)
- Xuanyi Li
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
| | - Changsong Xu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200030, China
| | - Boyu Liu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
| | - Xueyang Li
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Hongjun Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200030, China
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10
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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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11
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Gu P, Wang C, Su D, Dong Z, Wang Q, Han Z, Watanabe K, Taniguchi T, Ji W, Sun Y, Ye Y. Multi-state data storage in a two-dimensional stripy antiferromagnet implemented by magnetoelectric effect. Nat Commun 2023; 14:3221. [PMID: 37270582 DOI: 10.1038/s41467-023-39004-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/25/2023] [Indexed: 06/05/2023] Open
Abstract
A promising approach to the next generation of low-power, functional, and energy-efficient electronics relies on novel materials with coupled magnetic and electric degrees of freedom. In particular, stripy antiferromagnets often exhibit broken crystal and magnetic symmetries, which may bring about the magnetoelectric (ME) effect and enable the manipulation of intriguing properties and functionalities by electrical means. The demand for expanding the boundaries of data storage and processing technologies has led to the development of spintronics toward two-dimensional (2D) platforms. This work reports the ME effect in the 2D stripy antiferromagnetic insulator CrOCl down to a single layer. By measuring the tunneling resistance of CrOCl on the parameter space of temperature, magnetic field, and applied voltage, we verified the ME coupling down to the 2D limit and probed its mechanism. Utilizing the multi-stable states and ME coupling at magnetic phase transitions, we realize multi-state data storage in the tunneling devices. Our work not only advances the fundamental understanding of spin-charge coupling, but also demonstrates the great potential of 2D antiferromagnetic materials to deliver devices and circuits beyond the traditional binary operations.
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Affiliation(s)
- Pingfan Gu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Cong Wang
- Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, China
| | - Dan Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Beijing, China
| | - Zehao Dong
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Qiuyuan Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China
| | - Zheng Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Optoelectronics, Taiyuan, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China
- Liaoning Academy of Materials, Shenyang, China
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, China.
| | - Young Sun
- Center of Quantum Materials and Devices, and Department of Applied Physics, Chongqing University, Chongqing, China.
| | - Yu Ye
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
- Liaoning Academy of Materials, Shenyang, China.
- Yangtze Delta Institute of Optoelectronics, Peking University, Nantong, China.
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12
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Jiang S, Wang G, Deng H, Liu K, Yang Q, Zhao E, Zhu L, Guo W, Yang J, Zhang C, Wang H, Zhang X, Dai JF, Luo G, Zhao Y, Lin J. General Synthesis of 2D Magnetic Transition Metal Dihalides via Trihalide Reduction. ACS NANO 2023; 17:363-371. [PMID: 36576433 DOI: 10.1021/acsnano.2c08693] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) transition metal dihalides (TMDHs) have been receiving extensive attention due to their diversified magnetic properties and promising applications in spintronics. However, controlled growth of 2D TMDHs remains challenging owing to their extreme sensitivity to atmospheric moisture. Herein, using a home-built nitrogen-filled interconnected glovebox system, a universal chemical vapor deposition synthesis route of high-quality 2D TMDH flakes (1T-FeCl2, FeBr2, VCl2, and VBr2) by reduction of their trihalide counterparts is developed. Representatively, ultrathin (∼8.6 nm) FeCl2 flakes are synthesized on SiO2/Si, while on graphene/Cu foil the thickness can be down to monolayer (1L). Reflective magnetic circular dichroism spectroscopy shows an interlayer antiferromagnetic ordering of FeCl2 with a Neel temperature at ∼17 K. Scanning tunneling microscopy and spectroscopy further identify the atomic-scale structures and band features of 1L and bilayer FeCl2 on graphene/Cu foil.
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Affiliation(s)
- Shaolong Jiang
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Gang Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Hanbing Deng
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
| | - Kai Liu
- Department of Materials Science and Engineering and Guangdong Provincial Key Laboratory of Computational Science and Material Design, Southern University of Science and Technology, Shenzhen518055, China
| | - Qishuo Yang
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Erding Zhao
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Liang Zhu
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Weiteng Guo
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Jing Yang
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
| | - Cheng Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen518055, China
| | - Heshen Wang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen518055, China
| | - Xi Zhang
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen518055, China
| | - Jun-Feng Dai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen518055, China
| | - Guangfu Luo
- Department of Materials Science and Engineering and Guangdong Provincial Key Laboratory of Computational Science and Material Design, Southern University of Science and Technology, Shenzhen518055, China
| | - Yue Zhao
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
| | - Junhao Lin
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen518055, China
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13
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Zhao Y, Liu Q, Zhang F, Jiang X, Gao W, Zhao J. Multiferroicity in a Two-Dimensional Non-van der Waals Crystal of AgCr 2X 4 (X = S or Se). J Phys Chem Lett 2022; 13:11346-11353. [PMID: 36454027 DOI: 10.1021/acs.jpclett.2c03160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) intrinsic multiferroics have long been pursued not only for their potential technological applications but also as model systems for studying emergent quantum phenomena and coupling mechanisms between various order parameters in low-dimensional space. However, the realization of 2D multiferroics is still a challenge. In this paper, we reveal that 2D AgCr2X4 (X = S or Se) crystals, which have been synthesized from the non-van der Waals (non-vdW) AgCrX2 bulk phase, are type I half-metallic/metallic multiferroics in which ferroelectricity and ferromagnetism coexist. The off-centering displacement of the Ag ion introduces out-of-plane polarization, and the magnetism originates from the interactions between Cr atoms. Remarkably, AgCr2Se4 shows topologically nontrivial spin textures, such as Meron pairs and Néel-type skyrmions, under suitable temperatures and magnetic fields. Our findings demonstrate that 2D multiferroics can be achieved from non-vdW materials and in turn open a new avenue for 2D multiferroics.
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Affiliation(s)
- Ying Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
| | - Qinxi Liu
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
| | - Fan Zhang
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
| | - Xue Jiang
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
| | - Weiwei Gao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian116024, China
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14
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Ni Z, Huang N, Haglund AV, Mandrus DG, Wu L. Observation of Giant Surface Second-Harmonic Generation Coupled to Nematic Orders in the van der Waals Antiferromagnet FePS 3. NANO LETTERS 2022; 22:3283-3288. [PMID: 35413201 DOI: 10.1021/acs.nanolett.2c00212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Second-harmonic generation has been applied to study lattice, electronic, and magnetic proprieties in atomically thin materials. However, inversion symmetry breaking is usually required for the materials to generate a large signal. In this work, we report a giant second-harmonic generation that arises below the Néel temperature in few-layer centrosymmetric FePS3. A layer-dependent study indicates the detected signal is from the second-order nonlinearity of the surface. The magnetism-induced surface second-harmonic response is 2 orders of magnitude larger than those reported in other magnetic systems, with the surface nonlinear susceptibility reaching 0.08-0.13 nm2/V in 2-5 L samples. By combing linear dichroism and second-harmonic generation experiments, we further confirm the giant second-harmonic generation is coupled to nematic orders formed by the three possible Zigzag antiferromagnetic domains. Our study shows that the surface second-harmonic generation is also a sensitive tool to study antiferromagnetic states in centrosymmetric atomically thin materials.
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Affiliation(s)
- Zhuoliang Ni
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Nan Huang
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Amanda V Haglund
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - David G Mandrus
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Liang Wu
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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15
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Son S, Lee Y, Kim JH, Kim BH, Kim C, Na W, Ju H, Park S, Nag A, Zhou KJ, Son YW, Kim H, Noh WS, Park JH, Lee JS, Cheong H, Kim JH, Park JG. Multiferroic-Enabled Magnetic-Excitons in 2D Quantum-Entangled Van der Waals Antiferromagnet NiI 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109144. [PMID: 34936713 DOI: 10.1002/adma.202109144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Matter-light interaction is at the center of diverse research fields from quantum optics to condensed matter physics, opening new fields like laser physics. A magnetic exciton is one such rare example found in magnetic insulators. However, it is relatively rare to observe that external variables control matter-light interaction. Here, it is reported that the broken inversion symmetry of multiferroicity can act as an external knob enabling magnetic excitons in the van der Waals antiferromagnet NiI2 . It is further discovered that this magnetic exciton arises from a transition between Zhang-Rice-triplet and Zhang-Rice-singlet fundamentally quantum-entangled states. This quantum entanglement produces an ultrasharp optical exciton peak at 1.384 eV with a 5 meV linewidth. The work demonstrates that NiI2 is 2D magnetically ordered with an intrinsically quantum-entangled ground state.
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Affiliation(s)
- Suhan Son
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Youjin Lee
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jae Ha Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Beom Hyun Kim
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Chaebin Kim
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Woongki Na
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Hwiin Ju
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Sudong Park
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
| | - Abhishek Nag
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - Young-Woo Son
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Hyeongdo Kim
- XFEL Beamline Division, Pohang Accelerator Laboratory, Pohang, 37673, Republic of Korea
| | - Woo-Suk Noh
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
| | - Jae-Hoon Park
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
| | - Jong Seok Lee
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Jae Hoon Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Je-Geun Park
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
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16
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Song Q, Occhialini CA, Ergeçen E, Ilyas B, Amoroso D, Barone P, Kapeghian J, Watanabe K, Taniguchi T, Botana AS, Picozzi S, Gedik N, Comin R. Evidence for a single-layer van der Waals multiferroic. Nature 2022; 602:601-605. [PMID: 35197619 DOI: 10.1038/s41586-021-04337-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 12/10/2021] [Indexed: 11/09/2022]
Abstract
Multiferroic materials have attracted wide interest because of their exceptional static1-3 and dynamical4-6 magnetoelectric properties. In particular, type-II multiferroics exhibit an inversion-symmetry-breaking magnetic order that directly induces ferroelectric polarization through various mechanisms, such as the spin-current or the inverse Dzyaloshinskii-Moriya effect3,7. This intrinsic coupling between the magnetic and dipolar order parameters results in high-strength magnetoelectric effects3,8. Two-dimensional materials possessing such intrinsic multiferroic properties have been long sought for to enable the harnessing of magnetoelectric coupling in nanoelectronic devices1,9,10. Here we report the discovery of type-II multiferroic order in a single atomic layer of the transition-metal-based van der Waals material NiI2. The multiferroic state of NiI2 is characterized by a proper-screw spin helix with given handedness, which couples to the charge degrees of freedom to produce a chirality-controlled electrical polarization. We use circular dichroic Raman measurements to directly probe the magneto-chiral ground state and its electromagnon modes originating from dynamic magnetoelectric coupling. Combining birefringence and second-harmonic-generation measurements with theoretical modelling and simulations, we detect a highly anisotropic electronic state that simultaneously breaks three-fold rotational and inversion symmetry, and supports polar order. The evolution of the optical signatures as a function of temperature and layer number surprisingly reveals an ordered magnetic polar state that persists down to the ultrathin limit of monolayer NiI2. These observations establish NiI2 and transition metal dihalides as a new platform for studying emergent multiferroic phenomena, chiral magnetic textures and ferroelectricity in the two-dimensional limit.
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Affiliation(s)
- Qian Song
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Connor A Occhialini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Emre Ergeçen
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Batyr Ilyas
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Danila Amoroso
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi 'G. D'Annunzio', Chieti, Italy.,NanoMat/Q-mat/CESAM, Université de Liège, Liège, Belgium
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche CNR-SPIN, Area della Ricerca di Tor Vergata, Rome, Italy
| | - Jesse Kapeghian
- Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Antia S Botana
- Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi 'G. D'Annunzio', Chieti, Italy
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
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17
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Tahir R, Zahra SA, Naeem U, Akinwande D, Rizwan S. First observation on emergence of strong room-temperature ferroelectricity and multiferroicity in 2D-Ti 3C 2T x free-standing MXene film. RSC Adv 2022; 12:24571-24578. [PMID: 36128398 PMCID: PMC9426648 DOI: 10.1039/d2ra04428e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/16/2022] [Indexed: 11/26/2022] Open
Abstract
Two-dimensional (2D) multiferroics are key candidate materials towards advancement of smart technology. Here, we employed a simple synthesis approach to address the long-awaited dream of developing ferroelectric and multiferroic 2D materials, especially in the new class of materials called MXenes. The etched Ti3C2Tx MXene was first synthesized after HF-treatment followed by a delamination process for successful synthesis of free-standing Ti3C2Tx film. The free-standing film was then exposed to air at room-temperature and heated at different temperatures to form a TiO2 layer derived from the Ti3C2Tx MXene itself. The ferroelectric measurement showed a clear polarization hysteresis loop at room-temperature. Also, due to the reported ferromagnetic behavior of Ti3C2Tx MXene, our composite could show multiferroic properties at room-temperature. The magnetoelectric coupling test was also performed that showed a clear, switchable spontaneous polarization under applied magnetic field. TiO2 is reported to be an incipient ferroelectric that assumes a ferroelectric phase in composite form. The structural and morphological analysis confirmed successful synthesis of free-standing film and the Raman spectroscopy revealed the formation of different phases of TiO2 and the observed ferroelectricity could be due to structural deformation as a result of the formation of this new phase. The measured value of remanent polarization is 0.5 μC cm−2. This is the first report on the existence of a ferroelectric phase and multiferroic coupling in 2D free-standing MXene film at room-temperature which opens-up the possibility of 2D material-based electric and magnetic data storage applications at room-temperature. Two-dimensional (2D) multiferroics are key candidate materials towards advancement of smart technology.![]()
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Affiliation(s)
- Rabia Tahir
- Physics Characterization and Simulations Lab (PCSL), Department of Physics, School of Natural Sciences, National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
| | - Syedah Afsheen Zahra
- Physics Characterization and Simulations Lab (PCSL), Department of Physics, School of Natural Sciences, National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
| | - Usman Naeem
- Physics Characterization and Simulations Lab (PCSL), Department of Physics, School of Natural Sciences, National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
| | - Deji Akinwande
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX 78758, USA
| | - Syed Rizwan
- Physics Characterization and Simulations Lab (PCSL), Department of Physics, School of Natural Sciences, National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
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18
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Hur JH. First-principles study on multiferroicity in the Cr 2Ge 2Te 6/In 2Se 3 heterostructure influenced by finite strains. Phys Chem Chem Phys 2021; 23:25925-25932. [PMID: 34782900 DOI: 10.1039/d1cp04332c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiferroic materials that have more than two ferroicities at the same time have long been regarded as one of the strongest candidates to achieve technological breakthroughs in many kinds of nanodevice applications. Various types of multiferroic materials have been discovered and devised to date; however, related studies have been conducted without identifying a complete winner because each has a decisive disadvantage. The recently discovered multiferroicity in the 2D Cr2Ge2Te6/In2Se3 van der Waals heterostructure represents an important opportunity to create a new turning point in multiferroic research. Through first-principles density functional theory calculations, we studied the preferential characteristics of the spin magnetic moment of 2D Cr2Ge2Te6 induced by the ferroelectric switching of the In2Se3 monolayer in the presence of the strains that inevitably exist in any kind of heterostructure. From the results, we found that the multiferroicity in the Cr2Ge2Te6/In2Se3 heterostructure reacts quite sensitively to the strain level, revealing the possibility of manipulating multiferroic properties in the structure.
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Affiliation(s)
- Ji-Hyun Hur
- Department of Electrical Engineering, Sejong University, 209, Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea.,Hur Advanced Research, 96, Dongtanbanseok-ro, Hwaseong-si, Gyeonggi-do, 18456, Republic of Korea.
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19
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Amoroso D, Barone P, Picozzi S. Interplay between Single-Ion and Two-Ion Anisotropies in Frustrated 2D Semiconductors and Tuning of Magnetic Structures Topology. NANOMATERIALS 2021; 11:nano11081873. [PMID: 34443704 PMCID: PMC8397980 DOI: 10.3390/nano11081873] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 01/14/2023]
Abstract
The effects of competing magnetic interactions in stabilizing different spin configurations are drawing renewed attention in order to unveil emerging topological spin textures and to highlight microscopic mechanisms leading to their stabilization. The possible key role of the two-site exchange anisotropy in selecting specific helicity and vorticity of skyrmionic lattices has only recently been proposed. In this work, we explore the phase diagram of a frustrated localized magnet characterized by a two-dimensional centrosymmetric triangular lattice, focusing on the interplay between the two-ion anisotropy and the single-ion anisotropy. The effects of an external magnetic field applied perpendicularly to the magnetic layer, are also investigated. By means of Monte Carlo simulations, we find an abundance of different spin configurations, going from trivial to high-order Q skyrmionic and meronic lattices. In closer detail, we find that a dominant role is played by the two-ion over the single-ion anisotropy in determining the planar spin texture; the strength and the sign of single ion anisotropy, together with the magnitude of the magnetic field, tune the perpendicular spin components, mostly affecting the polarity (and, in turn, the topology) of the spin texture. Our analysis confirms the crucial role of the anisotropic symmetric exchange in systems with dominant short-range interactions; at the same time, we predict a rich variety of complex magnetic textures, which may arise from a fine tuning of competing anisotropic mechanisms.
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Affiliation(s)
- Danila Amoroso
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
- Correspondence:
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche CNR-SPIN, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, I-00133 Rome, Italy;
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN, c/o Università degli Studi “G. D’Annunzio”, I-66100 Chieti, Italy;
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