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Abstract
Abstract
Hexagonal manganites belong to an exciting class of materials exhibiting strong interactions between a highly frustrated magnetic system, the ferroelectric polarization, and the lattice. The existence and mutual interaction of different magnetic ions (Mn and rare earth) results in complex magnetic phase diagrams and novel physical phenomena. A summary and discussion of the various properties, underlying physical mechanisms, the role of the rare earth ions, and the complex interactions in multiferroic hexagonal manganites are presented in this review.
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Zheng Y, Chen WJ. Characteristics and controllability of vortices in ferromagnetics, ferroelectrics, and multiferroics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:086501. [PMID: 28155849 DOI: 10.1088/1361-6633/aa5e03] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Topological defects in condensed matter are attracting e significant attention due to their important role in phase transition and their fascinating characteristics. Among the various types of matter, ferroics which possess a switchable physical characteristic and form domain structure are ideal systems to form topological defects. In particular, a special class of topological defects-vortices-have been found to commonly exist in ferroics. They often manifest themselves as singular regions where domains merge in large systems, or stabilize as novel order states instead of forming domain structures in small enough systems. Understanding the characteristics and controllability of vortices in ferroics can provide us with deeper insight into the phase transition of condensed matter and also exciting opportunities in designing novel functional devices such as nano-memories, sensors, and transducers based on topological defects. In this review, we summarize the recent experimental and theoretical progress in ferroic vortices, with emphasis on those spin/dipole vortices formed in nanoscale ferromagnetics and ferroelectrics, and those structural domain vortices formed in multiferroic hexagonal manganites. We begin with an overview of this field. The fundamental concepts of ferroic vortices, followed by the theoretical simulation and experimental methods to explore ferroic vortices, are then introduced. The various characteristics of vortices (e.g. formation mechanisms, static/dynamic features, and electronic properties) and their controllability (e.g. by size, geometry, external thermal, electrical, magnetic, or mechanical fields) in ferromagnetics, ferroelectrics, and multiferroics are discussed in detail in individual sections. Finally, we conclude this review with an outlook on this rapidly developing field.
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Affiliation(s)
- Yue Zheng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China. Micro&Nano Physics and Mechanics Research Laboratory, School of Physics, Sun Yat-sen University, Guangzhou 510275, Guangdong, People's Republic of China
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Wu X, Petralanda U, Zheng L, Ren Y, Hu R, Cheong SW, Artyukhin S, Lai K. Low-energy structural dynamics of ferroelectric domain walls in hexagonal rare-earth manganites. SCIENCE ADVANCES 2017; 3:e1602371. [PMID: 28508057 PMCID: PMC5425234 DOI: 10.1126/sciadv.1602371] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 03/03/2017] [Indexed: 05/29/2023]
Abstract
Domain walls (DWs) in ferroic materials, across which the order parameter abruptly changes its orientation, can host emergent properties that are absent in the bulk domains. Using a broadband (106 to 1010 Hz) scanning impedance microscope, we show that the electrical response of the interlocked antiphase boundaries and ferroelectric DWs in hexagonal rare-earth manganites (h-RMnO3) is dominated by the bound-charge oscillation rather than free-carrier conduction at the DWs. As a measure of the rate of energy dissipation, the effective conductivity of DWs on the (001) surfaces of h-RMnO3 at gigahertz frequencies is drastically higher than that at dc, whereas the effect is absent on surfaces with in-plane polarized domains. First-principles and model calculations indicate that the frequency range and selection rules are consistent with the periodic sliding of the DW around its equilibrium position. This acoustic wave-like mode, which is associated with the synchronized oscillation of local polarization and apical oxygen atoms, is localized perpendicular to the DW but free to propagate along the DW plane. Our results break the ground to understand structural DW dynamics and exploit new interfacial phenomena for novel devices.
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Affiliation(s)
- Xiaoyu Wu
- Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Urko Petralanda
- Quantum Materials Theory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Lu Zheng
- Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Yuan Ren
- Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Rongwei Hu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - Sergey Artyukhin
- Quantum Materials Theory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Keji Lai
- Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
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Sim H, Oh J, Jeong J, Le MD, Park JG. Hexagonal RMnO3: a model system for two-dimensional triangular lattice antiferromagnets. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2016; 72:3-19. [PMID: 26830792 DOI: 10.1107/s2052520615022106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/19/2015] [Indexed: 06/05/2023]
Abstract
The hexagonal RMnO3(h-RMnO3) are multiferroic materials, which exhibit the coexistence of a magnetic order and ferroelectricity. Their distinction is in their geometry that both results in an unusual mechanism to break inversion symmetry and also produces a two-dimensional triangular lattice of Mn spins, which is subject to geometrical magnetic frustration due to the antiferromagnetic interactions between nearest-neighbor Mn ions. This unique combination makes the h-RMnO3 a model system to test ideas of spin-lattice coupling, particularly when both the improper ferroelectricity and the Mn trimerization that appears to determine the symmetry of the magnetic structure arise from the same structure distortion. In this review we demonstrate how the use of both neutron and X-ray diffraction and inelastic neutron scattering techniques have been essential to paint this comprehensive and coherent picture of h-RMnO3.
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Affiliation(s)
- Hasung Sim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Joosung Oh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Jaehong Jeong
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Manh Duc Le
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Je Geun Park
- Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
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Xue F, Wang X, Socolenco I, Gu Y, Chen LQ, Cheong SW. Evolution of the statistical distribution in a topological defect network. Sci Rep 2015; 5:17057. [PMID: 26586339 PMCID: PMC4653636 DOI: 10.1038/srep17057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/21/2015] [Indexed: 11/12/2022] Open
Abstract
The complex networks of numerous topological defects in hexagonal manganites are highly relevant to vastly different phenomena from the birth of our cosmos to superfluidity transition. The topological defects in hexagonal manganites form two types of domain networks: type-I without and type-II with electric self-poling. A combined phase-field simulations and experimental study shows that the frequencies of domains with N-sides, i.e. of N-gons, in a type-I network are fitted by a lognormal distribution, whereas those in type-II display a scale-free power-law distribution with exponent ∼2. A preferential attachment process that N-gons with a larger N have higher probability of coalescence is responsible for the emergence of the scale-free networks. Since the domain networks can be observed, analyzed, and manipulated at room temperature, hexagonal manganites provide a unique opportunity to explore how the statistical distribution of a topological defect network evolves with an external electric field.
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Affiliation(s)
- Fei Xue
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Xueyun Wang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Ion Socolenco
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Yijia Gu
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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Huang FT, Wang X, Griffin SM, Kumagai Y, Gindele O, Chu MW, Horibe Y, Spaldin NA, Cheong SW. Duality of topological defects in hexagonal manganites. PHYSICAL REVIEW LETTERS 2014; 113:267602. [PMID: 25615384 DOI: 10.1103/physrevlett.113.267602] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Indexed: 06/04/2023]
Abstract
We show that the spontaneous symmetry breaking in multiferroic hexagonal manganites can be chemically manipulated to yield two complementary ground states: the well-known ferroelectric P6(3)cm and an antipolar P3c phase. Both symmetry breakings yield topologically protected vortex defects, with the antipolar vortices dual to those of the ferroelectric. This duality stems from the existence of 12 possible angles of MnO5 tilting, and broad strain-free walls with low energy spontaneously emerge through an intermediate P3c1 state, providing a complete unified symmetry description.
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Affiliation(s)
- Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Xueyun Wang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Sinead M Griffin
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Yu Kumagai
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Oliver Gindele
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Ming-Wen Chu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Yoichi Horibe
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Nicola A Spaldin
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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Liu J, Chen W, Wang B, Zheng Y. Theoretical Methods of Domain Structures in Ultrathin Ferroelectric Films: A Review. MATERIALS (BASEL, SWITZERLAND) 2014; 7:6502-6568. [PMID: 28788198 PMCID: PMC5456131 DOI: 10.3390/ma7096502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 07/31/2014] [Accepted: 08/18/2014] [Indexed: 11/21/2022]
Abstract
This review covers methods and recent developments of the theoretical study of domain structures in ultrathin ferroelectric films. The review begins with an introduction to some basic concepts and theories (e.g., polarization and its modern theory, ferroelectric phase transition, domain formation, and finite size effects, etc.) that are relevant to the study of domain structures in ultrathin ferroelectric films. Basic techniques and recent progress of a variety of important approaches for domain structure simulation, including first-principles calculation, molecular dynamics, Monte Carlo simulation, effective Hamiltonian approach and phase field modeling, as well as multiscale simulation are then elaborated. For each approach, its important features and relative merits over other approaches for modeling domain structures in ultrathin ferroelectric films are discussed. Finally, we review recent theoretical studies on some important issues of domain structures in ultrathin ferroelectric films, with an emphasis on the effects of interfacial electrostatics, boundary conditions and external loads.
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Affiliation(s)
- Jianyi Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Weijin Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Biao Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Yue Zheng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
- Micro & Nano Physics and Mechanics Research Laboratory, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
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Zhang Q, Tan G, Gu L, Yao Y, Jin C, Wang Y, Duan X, Yu R. Direct observation of multiferroic vortex domains in YMnO3. Sci Rep 2014; 3:2741. [PMID: 24061552 PMCID: PMC3781397 DOI: 10.1038/srep02741] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/05/2013] [Indexed: 12/02/2022] Open
Abstract
Topological vortices with swirling ferroelectric, magnetic and structural anti-phase relationship in hexagonal RMnO3 (R = Ho to Lu, Y, and Sc) have attracted much attention because of their intriguing behaviors. Herein, we report the structure of multiferroic vortex domains in YMnO3 at atomic scale using state-of-the-art aberration-corrected scanning transmission electron microscopy (STEM). Two types of displacements were identified among six domain walls (DWs); six translation-ferroelectric domains denoted by α+, γ−, β+, α−, γ+ and β−, respectively, were recognized, demonstrating the interlocking nature of the anti-vortex domain. We found that the anti-vortex core is about four unit cells wide. In addition, we reconstructed the vortex model with three swirling pairs of DWs along the [001] direction. These results are very critical for the understanding of topological behaviors and unusual properties of the multiferroic vortex.
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Affiliation(s)
- Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
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Wang X, Mostovoy M, Han MG, Horibe Y, Aoki T, Zhu Y, Cheong SW. Unfolding of vortices into topological stripes in a multiferroic material. PHYSICAL REVIEW LETTERS 2014; 112:247601. [PMID: 24996108 DOI: 10.1103/physrevlett.112.247601] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Indexed: 06/03/2023]
Abstract
Multiferroic hexagonal RMnO(3) (R=rare earths) crystals exhibit dense networks of vortex lines at which six domain walls merge. While the domain walls can be readily moved with an applied electric field, the vortex cores so far have been impossible to control. Our experiments demonstrate that shear strain induces a Magnus-type force pulling vortices and antivortices in opposite directions and unfolding them into a topological stripe domain state. We discuss the analogy between this effect and the current-driven dynamics of vortices in superconductors and superfluids.
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Affiliation(s)
- X Wang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - M Mostovoy
- Zernile Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - M G Han
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Y Horibe
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - T Aoki
- JEOL USA, Inc., Peabody, Massachusetts 01960, USA
| | - Y Zhu
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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Horibe Y, Yang J, Cho YH, Luo X, Kim SB, Oh YS, Huang FT, Asada T, Tanimura M, Jeong D, Cheong SW. Color Theorems, Chiral Domain Topology, and Magnetic Properties of FexTaS2. J Am Chem Soc 2014; 136:8368-73. [DOI: 10.1021/ja5026134] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoichi Horibe
- Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Junjie Yang
- Laboratory
for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department
of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Yong-Heum Cho
- Laboratory
for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department
of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Xuan Luo
- Laboratory
for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department
of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Sung Baek Kim
- Laboratory
for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department
of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Yoon Seok Oh
- Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Toshihiro Asada
- Research
Department, Nissan Arc, Ltd., Yokosuka, Kanagawa 237-0061, Japan
| | - Makoto Tanimura
- Research
Department, Nissan Arc, Ltd., Yokosuka, Kanagawa 237-0061, Japan
| | - Dalyoung Jeong
- Department
of Mathematics, Soongsil University, Seoul 156-743, Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
- Laboratory
for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
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Geng Y, Das H, Wysocki AL, Wang X, Cheong SW, Mostovoy M, Fennie CJ, Wu W. Direct visualization of magnetoelectric domains. NATURE MATERIALS 2014; 13:163-167. [PMID: 24292421 DOI: 10.1038/nmat3813] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 10/17/2013] [Indexed: 06/02/2023]
Abstract
The coupling between the magnetic and electric dipoles in multiferroic and magnetoelectric materials holds promise for conceptually novel electronic devices. This calls for the development of local probes of the magnetoelectric response, which is strongly affected by defects in magnetic and ferroelectric ground states. For example, multiferroic hexagonal rare earth manganites exhibit a dense network of boundaries between six degenerate states of their crystal lattice, which are locked to both ferroelectric and magnetic domain walls. Here we present the application of a magnetoelectric force microscopy technique that combines magnetic force microscopy with in situ modulating high electric fields. This method allows us to image the magnetoelectric response of the domain patterns in hexagonal manganites directly. We find that this response changes sign at each structural domain wall, a result that is corroborated by symmetry analysis and phenomenological modelling, and provides compelling evidence for a lattice-mediated magnetoelectric coupling. The direct visualization of magnetoelectric domains at mesoscopic scales opens up explorations of emergent phenomena in multifunctional materials with multiple coupled orders.
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Affiliation(s)
- Yanan Geng
- Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Hena Das
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, 14853, USA
| | - Aleksander L Wysocki
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, 14853, USA
| | - Xueyun Wang
- Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
| | - S-W Cheong
- Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
| | - M Mostovoy
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Craig J Fennie
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York, 14853, USA
| | - Weida Wu
- Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
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