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Zhang X, Carbin T, Culver AB, Du K, Wang K, Cheong SW, Roy R, Kogar A. Light-induced electronic polarization in antiferromagnetic Cr 2O 3. Nat Mater 2024:10.1038/s41563-024-01852-w. [PMID: 38561519 DOI: 10.1038/s41563-024-01852-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
In a solid, the electronic subsystem can exhibit incipient order with lower point group symmetry than the crystal lattice. Ultrafast external fields that couple exclusively to electronic order parameters have rarely been investigated, however, despite their potential importance in inducing exotic effects. Here we show that when inversion symmetry is broken by the antiferromagnetic order in Cr2O3, transmitting a linearly polarized light pulse through the crystal gives rise to an in-plane rotational symmetry-breaking (from C3 to C1) via optical rectification. Using interferometric time-resolved second harmonic generation, we show that the ultrafast timescale of the symmetry reduction is indicative of a purely electronic response; the underlying spin and crystal structures remain unaffected. The symmetry-broken state exhibits a dipole moment, and its polar axis can be controlled with the incident light. Our results establish a coherent nonlinear optical protocol by which to break electronic symmetries and produce unconventional electronic effects in solids.
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Affiliation(s)
- Xinshu Zhang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Tyler Carbin
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Adrian B Culver
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
- Mani L. Bhaumik Institute for Theoretical Physics, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Kai Du
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Kefeng Wang
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Rahul Roy
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
- Mani L. Bhaumik Institute for Theoretical Physics, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Anshul Kogar
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA.
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2
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Choi GS, Park S, An ES, Bae J, Shin I, Kang BT, Won CJ, Cheong SW, Lee HW, Lee GH, Cho WJ, Kim JS. Highly Efficient Room-Temperature Spin-Orbit-Torque Switching in a Van der Waals Heterostructure of Topological Insulator and Ferromagnet. Adv Sci (Weinh) 2024:e2400893. [PMID: 38520060 DOI: 10.1002/advs.202400893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 03/25/2024]
Abstract
All-Van der Waals (vdW)-material-based heterostructures with atomically sharp interfaces offer a versatile platform for high-performing spintronic functionalities at room temperature. One of the key components is vdW topological insulators (TIs), which can produce a strong spin-orbit-torque (SOT) through the spin-momentum locking of their topological surface state (TSS). However, the relatively low conductance of the TSS introduces a current leakage problem through the bulk states of the TI or the adjacent ferromagnetic metal layers, reducing the interfacial charge-to-spin conversion efficiency (qICS). Here, a vdW heterostructure is used consisting of atomically-thin layers of a bulk-insulating TI Sn-doped Bi1.1Sb0.9Te2S1 and a room-temperature ferromagnet Fe3GaTe2, to enhance the relative current ratio on the TSS up to ≈20%. The resulting qICS reaches ≈1.65 nm-1 and the critical current density Jc ≈0.9 × 106 Acm-2 at 300 K, surpassing the performance of TI-based and heavy-metal-based SOT devices. These findings demonstrate that an all-vdW heterostructure with thickness optimization offers a promising platform for efficient current-controlled magnetization switching at room temperature.
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Affiliation(s)
- Gyu Seung Choi
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sungyu Park
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Eun-Su An
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Juhong Bae
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Inseob Shin
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Beom Tak Kang
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Choong Jae Won
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Won Joon Cho
- Device Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
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3
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Lee J, Park HR, Jin KH, Kim JS, Cheong SW, Yeom HW. Topological Complex Charge Conservation in Nontrivial Z 2 × Z 2 Domain Walls. Adv Mater 2024:e2313803. [PMID: 38482920 DOI: 10.1002/adma.202313803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/14/2024] [Indexed: 03/22/2024]
Abstract
Localized topological modes such as solitons, Majorana Fermions, and skyrmions are attracting great interest as robust information carriers for future devices. Here, a novel conserved quantity for topological domain wall networks of a Z2 × Z2 order generated with spin-polarized current in Sr2VO3FeAs is discovered. Domain walls are mobilized by the scanning tunneling current, which also observes in atomic scale active dynamics of domain wall vertices including merge, bifurcation, pair creation, and annihilation. Within this dynamics, the product of the topological complex charges defined for domain wall vertices is conserved with a novel boundary-charge correspondence rule. These results may open an avenue toward topological electronics based on domain wall vertices in generic Z2 × Z2 systems.
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Affiliation(s)
- Jhinhwan Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Hae-Ryong Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Han-Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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4
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Lim S, Singh S, Huang FT, Pan S, Wang K, Kim J, Kim J, Vanderbilt D, Cheong SW. Magnetochiral tunneling in paramagnetic Co 1/3NbS 2. Proc Natl Acad Sci U S A 2024; 121:e2318443121. [PMID: 38412131 DOI: 10.1073/pnas.2318443121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/25/2024] [Indexed: 02/29/2024] Open
Abstract
Electric currents have the intriguing ability to induce magnetization in nonmagnetic crystals with sufficiently low crystallographic symmetry. Some associated phenomena include the non-linear anomalous Hall effect in polar crystals and the nonreciprocal directional dichroism in chiral crystals when magnetic fields are applied. In this work, we demonstrate that the same underlying physics is also manifested in the electronic tunneling process between the surface of a nonmagnetic chiral material and a magnetized scanning probe. In the paramagnetic but chiral metallic compound Co1/3NbS2, the magnetization induced by the tunneling current is shown to become detectable by its coupling to the magnetization of the tip itself. This results in a contrast across different chiral domains, achieving atomic-scale spatial resolution of structural chirality. To support the proposed mechanism, we used first-principles theory to compute the chirality-dependent current-induced magnetization and Berry curvature in the bulk of the material. Our demonstration of this magnetochiral tunneling effect opens up an avenue for investigating atomic-scale variations in the local crystallographic symmetry and electronic structure across the structural domain boundaries of low-symmetry nonmagnetic crystals.
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Affiliation(s)
- Seongjoon Lim
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - Sobhit Singh
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627
- Materials Science Program, University of Rochester, Rochester, NY 14627
| | - Fei-Ting Huang
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - Shangke Pan
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
- State Key Laboratory Base of Novel Function Materials and Preparation Science, School of Material Sciences and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Kefeng Wang
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - Jaewook Kim
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - Jinwoong Kim
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - David Vanderbilt
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
| | - Sang-Wook Cheong
- Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854
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5
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Okamoto J, Wang RP, Chu YY, Shiu HW, Singh A, Huang HY, Mou CY, Teh S, Jeng HT, Du K, Xu X, Cheong SW, Du CH, Chen CT, Fujimori A, Huang DJ. Giant X-Ray Circular Dichroism in a Time-Reversal Invariant Antiferromagnet. Adv Mater 2024:e2309172. [PMID: 38391035 DOI: 10.1002/adma.202309172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 02/09/2024] [Indexed: 02/24/2024]
Abstract
X-ray circular dichroism, arising from the contrast in X-ray absorption between opposite photon helicities, serves as a spectroscopic tool to measure the magnetization of ferromagnetic materials and identify the handedness of chiral crystals. Antiferromagnets with crystallographic chirality typically lack X-ray magnetic circular dichroism because of time-reversal symmetry, yet exhibit weak X-ray natural circular dichroism. Here, the observation of giant natural circular dichroism in the Ni L3-edge X-ray absorption of Ni3TeO6 is reported, a polar and chiral antiferromagnet with effective time-reversal symmetry. To unravel this intriguing phenomenon, a phenomenological model is proposed that classifies the movement of photons in a chiral crystal within the same symmetry class as that of a magnetic field. The coupling of X-ray polarization with the induced magnetization yields giant X-ray natural circular dichroism, revealing typical ferromagnetic behaviors allowed by the symmetry in an antiferromagnet, i.e., the altermagnetism of Ni3TeO6. The findings provide evidence for the interplay between magnetism and crystal chirality in natural optical activity. Additionally, the first example of a new class of magnetic materials exhibiting circular dichroism is established with time-reversal symmetry.
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Affiliation(s)
- Jun Okamoto
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Ru-Pan Wang
- Department of Physics, University of Hamburg, Luruper Chaussee 149, G610, 22761, Hamburg, Germany
| | - Yen-Yi Chu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hung-Wei Shiu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Amol Singh
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hsiao-Yu Huang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chung-Yu Mou
- Center for Quantum Science and Technology and Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Sukhito Teh
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Kai Du
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Xianghan Xu
- 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
| | - Chao-Hung Du
- Department of Physics, Tamkang University, Tamsui, 251, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Atsushi Fujimori
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
- Center for Quantum Science and Technology and Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Department of Physics, University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan
| | - Di-Jing Huang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30093, Taiwan
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6
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Xu X, Huang FT, Cheong SW. Magnetic toroidicity. J Phys Condens Matter 2024; 36:203002. [PMID: 38290166 DOI: 10.1088/1361-648x/ad2426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 01/30/2024] [Indexed: 02/01/2024]
Abstract
Directional non-reciprocity refers to the phenomenon where the motion in one direction differs from the motion in the opposite direction. This behavior is observed across various systems, such as one-way traffic and materials displaying electronic/optical directional dichroism, characterized by the symmetry of velocity vectors. Magnetic toroidal moments (MTMs), which typically arise from rotational spin arrangements, also possess the symmetry of velocity vectors, making them inherently directionally non-reciprocal. In this paper, we examine magnetic point groups (MPGs) that exhibit MTMs, subsequently leading to off-diagonal linear magnetoelectricity. Our focus is on the induction of MTMs through electric fields, magnetic fields, or shear stress, while enumerating the relevant MPGs. The findings of our study will serve as valuable guidance for future investigations on directional non-reciprocity, MTMs, and off-diagonal linear magnetoelectric effects.
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Affiliation(s)
- Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
| | - Fei-Ting Huang
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
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7
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Dai Y, Xiong J, Ge Y, Cheng B, Wang L, Wang P, Liu Z, Yan S, Zhang C, Xu X, Shi Y, Cheong SW, Xiao C, Yang SA, Liang SJ, Miao F. Interfacial magnetic spin Hall effect in van der Waals Fe 3GeTe 2/MoTe 2 heterostructure. Nat Commun 2024; 15:1129. [PMID: 38321042 PMCID: PMC10847462 DOI: 10.1038/s41467-024-45318-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/19/2024] [Indexed: 02/08/2024] Open
Abstract
The spin Hall effect (SHE) allows efficient generation of spin polarization or spin current through charge current and plays a crucial role in the development of spintronics. While SHE typically occurs in non-magnetic materials and is time-reversal even, exploring time-reversal-odd (T-odd) SHE, which couples SHE to magnetization in ferromagnetic materials, offers a new charge-spin conversion mechanism with new functionalities. Here, we report the observation of giant T-odd SHE in Fe3GeTe2/MoTe2 van der Waals heterostructure, representing a previously unidentified interfacial magnetic spin Hall effect (interfacial-MSHE). Through rigorous symmetry analysis and theoretical calculations, we attribute the interfacial-MSHE to a symmetry-breaking induced spin current dipole at the vdW interface. Furthermore, we show that this linear effect can be used for implementing multiply-accumulate operations and binary convolutional neural networks with cascaded multi-terminal devices. Our findings uncover an interfacial T-odd charge-spin conversion mechanism with promising potential for energy-efficient in-memory computing.
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Affiliation(s)
- Yudi Dai
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Junlin Xiong
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yanfeng Ge
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, Singapore
| | - Bin Cheng
- Institute of Interdisciplinary Physical Sciences, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Lizheng Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Pengfei Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zenglin Liu
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Shengnan Yan
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Cuiwei Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Xianghan Xu
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Youguo Shi
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Sang-Wook Cheong
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Cong Xiao
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, SAR, China.
- Department of Physics, University of Hong Kong, Hong Kong, China.
- HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China.
| | - Shengyuan A Yang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, SAR, China
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Feng Miao
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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8
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Kwon S, Jung H, Lee S, Cho GY, Kong K, Won C, Cheong SW, Yeom HW. Dual Higgs modes entangled into a soliton lattice in CuTe. Nat Commun 2024; 15:984. [PMID: 38302482 PMCID: PMC10834594 DOI: 10.1038/s41467-024-45354-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/18/2024] [Indexed: 02/03/2024] Open
Abstract
Recently discovered Higgs particle is a key element in the standard model of elementary particles and its analogue in materials, massive Higgs mode, has elucidated intriguing collective phenomena in a wide range of materials with spontaneous symmetry breaking such as antiferromagnets, cold atoms, superconductors, superfluids, and charge density waves (CDW). As a straightforward extension beyond the standard model, multiple Higgs particles have been considered theoretically but not yet for Higgs modes. Here, we report the real-space observations, which suggest two Higgs modes coupled together with a soliton lattice in a solid. Our scanning tunneling microscopy reveals the 1D CDW state of an anisotropic transition metal monochalcogenide crystal CuTe is composed of two distinct but degenerate CDW structures by the layer inversion symmetry broken. More importantly, the amplitudes of each CDW structure oscillate in an out-of-phase fashion to result in a regular array of alternating domains with repeating phase-shift domain walls. This unusual finding is explained by the extra degeneracy in CDWs within the standard Landau theory of the free energy. The multiple and entangled Higgs modes demonstrate how novel collective modes can emerge in systems with distinct symmetries broken simultaneously.
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Affiliation(s)
- SeongJin Kwon
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Hyunjin Jung
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - SangJin Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Gil Young Cho
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - KiJeong Kong
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
| | - ChoongJae Won
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea
- Laboatory for Pohang Emergent Materials, POSTECH, Pohang, 37673, Korea
- MPPC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Korea
| | - Sang-Wook Cheong
- Laboatory for Pohang Emergent Materials, POSTECH, Pohang, 37673, Korea
- MPPC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, 08854, USA
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, 37673, Korea.
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea.
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9
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Gao Z, Zhang Y, Li X, Zhang X, Chen X, Du G, Hou F, Gu B, Lun Y, Zhao Y, Zhao Y, Qu Z, Jin K, Wang X, Chen Y, Liu Z, Huang H, Gao P, Mostovoy M, Hong J, Cheong SW, Wang X. Mechanical manipulation for ordered topological defects. Sci Adv 2024; 10:eadi5894. [PMID: 38170776 PMCID: PMC10796077 DOI: 10.1126/sciadv.adi5894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Randomly distributed topological defects created during the spontaneous symmetry breaking are the fingerprints to trace the evolution of symmetry, range of interaction, and order parameters in condensed matter systems. However, the effective mean to manipulate topological defects into ordered form is elusive due to the topological protection. Here, we establish a strategy to effectively align the topological domain networks in hexagonal manganites through a mechanical approach. It is found that the nanoindentation strain gives rise to a threefold Magnus-type force distribution, leading to a sixfold symmetric domain pattern by driving the vortex and antivortex in opposite directions. On the basis of this rationale, sizeable mono-chirality topological stripe is readily achieved by expanding the nanoindentation to scratch, directly transferring the randomly distributed topological defects into an ordered form. This discovery provides a mechanical strategy to manipulate topological protected domains not only on ferroelectrics but also on ferromagnets/antiferromagnets and ferroelastics.
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Affiliation(s)
- Ziyan Gao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yixuan Zhang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaomei Li
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiangping Zhang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xue Chen
- Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Guoshuai Du
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Fei Hou
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Baijun Gu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yingzhuo Lun
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yao Zhao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yingtao Zhao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhaoliang Qu
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Ke Jin
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaolei Wang
- Department of Physics and Optoelectronics, Faculty of Science, Beijing University of Technology, Beijing 100124, China
| | - Yabin Chen
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Zhanwei Liu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Houbing Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Peng Gao
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Maxim Mostovoy
- Zernile Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Jiawang Hong
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Xueyun Wang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
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10
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Fang X, De C, Huang FT, Xu X, Du K, Wang K, Li B, Cheong SW. Ferrorotational Selectivity in Ilmenites. J Am Chem Soc 2023; 145:28022-28029. [PMID: 38108596 DOI: 10.1021/jacs.3c08635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Unlike what happens in conventional ferroics, the ferrorotational (FR) domain manipulation and visualization in FR materials are nontrivial as they are invariant under both space-inversion and time-reversal operations. FR domains have recently been observed by using the linear electrogyration (EG) effect and X-ray diffraction (XRD) diffraction mapping. However, ferrorotational selectivity, such as the selective processing of the FR domains and direct visualization of the FR domains, e.g., under an optical microscope, would be the next step to study the FR domains and their possible applications in technology. Unexpectedly, we discovered that the microscopic FR structural distortions in ilmenite crystals can be directly coupled with macroscopic mechanical rotations in such a way that FR domains can be visualized under an optical microscope after innovative rotational polishing, a combined ion milling with a specific rotational polishing, or a twisting-induced fracturing process. Thus, the FR domains could be a unique medium to register the memory of a rotational mechanical process due to a novel selective coupling between its microscopic structural rotations and an external macroscopic rotation. Analogous to the important enantioselectivity in modern chemistry and the pharmaceutical industry, this newly discovered ferrorotational selectivity opens up opportunities for FR manipulation and new FR functionality-based applications.
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Affiliation(s)
- Xiaochen Fang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Chandan De
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Xianghan Xu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Kai Du
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Kefeng Wang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Bingqing Li
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
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11
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Nguyen TMH, Nguyen XN, Nguyen TH, Vu TKO, Le DH, Nguyen VM, Yang IS, Cheong SW. PCMW2D and 2D Raman correlation spectroscopy evidence for presence of spin-phonon coupling in hexagonal LuMnO 3. Spectrochim Acta A Mol Biomol Spectrosc 2023; 297:122753. [PMID: 37119613 DOI: 10.1016/j.saa.2023.122753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/27/2023] [Accepted: 04/12/2023] [Indexed: 05/14/2023]
Abstract
Two-dimensional correlation spectroscopy (2D-COS) and perturbation-correlation moving window two-dimensional correlation spectroscopy (PCMW2D) analysis are performed on the temperature-dependent Raman spectra of hexagonal LuMnO3 single crystal. Under the resonance with the on-site Mn d-d transitions, the correlation between the phonons which are relate to the vibration of Mn ions' bonds and spin-excitation peaks suggest a strong spin-phonon coupling in LuMnO3. The PCMW2D results clearly show that the significant change in phonons and spin-excitation peaks occurs around the Néel temperature and the spin reorientation transition. The multiple components in the broad spin-excitation peaks also suggest variations in spin symmetries in the ground state. Furthermore, we propose that the 2D-COS and PCMW2D Raman correlation spectroscopies provide a simple and powerful method for investigating the couplings and the transitions, which would be very important for understanding systematically the magnetoelectric properties of multiferroic materials.
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Affiliation(s)
- Thi Minh Hien Nguyen
- Institute of Physics, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam.
| | - Xuan Nghia Nguyen
- Institute of Physics, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam
| | - Thi Huyen Nguyen
- Institute of Physics, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam
| | - Thi Kim Oanh Vu
- Institute of Physics, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam
| | - Duc Huy Le
- Institute of Physics, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam
| | - Van Minh Nguyen
- Faculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Viet Nam
| | - In-Sang Yang
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea.
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and astronomy, Rutgers University, Piscataway, NJ 08854, USA
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12
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Du K, Huang FT, Gamage K, Yang J, Mostovoy M, Cheong SW. Strain-Control of Cycloidal Spin Order in a Metallic Van der Waals Magnet. Adv Mater 2023; 35:e2303750. [PMID: 37358066 DOI: 10.1002/adma.202303750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/06/2023] [Indexed: 06/27/2023]
Abstract
The manipulation of magnetism through strain control is a captivating area of research with potential applications for low-power devices that do not require dissipative currents. Recent investigations of insulating multiferroics have unveiled tunable relationships among polar lattice distortions, Dzyaloshinskii-Moriya interactions (DMI), and cycloidal spin orders that break inversion symmetry. These findings have raised the possibility of utilizing strain or strain gradient to manipulate intricate magnetic states by changing polarization. However, the effectiveness of manipulating cycloidal spin orders in "metallic" materials with screened magnetism-relevant electric polarization remains uncertain. In this study, the reversible strain control of cycloidal spin textures in a metallic van der Waals magnet, Cr1/3 TaS2 , through the modulation of polarization and DMI induced by strain is demonstrated. With thermally-induced biaxial strains and isothermally-applied uniaxial strains, systematic manipulation of the sign and wavelength of the cycloidal spin textures is realized, respectively. Additionally, unprecedented reflectivity reduction under strain and domain modification at a record-low current density are also discovered. These findings establish a connection between polarization and cycloidal spins in metallic materials and present a new avenue for utilizing the remarkable tunability of cycloidal magnetic textures and optical functionality in van der Waals metals with strain.
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Affiliation(s)
- Kai Du
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Kasun Gamage
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey, 07102, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey, 07102, USA
| | - Maxim Mostovoy
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands
| | - 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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13
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Smith KA, Ramkumar SP, Du K, Xu X, Cheong SW, Gilbert Corder SN, Bechtel HA, Nowadnick EA, Musfeldt JL. Real-Space Infrared Spectroscopy of Ferroelectric Domain Walls in Multiferroic h-(Lu,Sc)FeO 3. ACS Appl Mater Interfaces 2023; 15:7562-7571. [PMID: 36715538 DOI: 10.1021/acsami.2c19600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We employ synchrotron-based near-field infrared spectroscopy to image the phononic properties of ferroelectric domain walls in hexagonal (h) Lu0.6Sc0.4FeO3, and we compare our findings with a detailed symmetry analysis, lattice dynamics calculations, and prior models of domain-wall structure. Rather than metallic and atomically thin as observed in the rare-earth manganites, ferroelectric walls in h-Lu0.6Sc0.4FeO3 are broad and semiconducting, a finding that we attribute to the presence of an A-site substitution-induced intermediate phase that reduces strain and renders the interior of the domain wall nonpolar. Mixed Lu/Sc occupation on the A site also provides compositional heterogeneity over micron-sized length scales, and we leverage the fact that Lu and Sc cluster in different ratios to demonstrate that the spectral characteristics at the wall are robust even in different compositional regimes. This work opens the door to broadband imaging of physical and chemical heterogeneity in ferroics and represents an important step toward revealing the rich properties of these flexible defect states.
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Affiliation(s)
- Kevin A Smith
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Sriram P Ramkumar
- Department of Materials Science and Engineering, University of California, Merced, California 95343 United States
| | - Kai Du
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 United States
| | - Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 United States
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 United States
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854 United States
| | - Stephanie N Gilbert Corder
- Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Hans A Bechtel
- Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
| | - Elizabeth A Nowadnick
- Department of Materials Science and Engineering, University of California, Merced, California 95343 United States
| | - Janice L Musfeldt
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
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14
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Wang L, Xiong J, Cheng B, Dai Y, Wang F, Pan C, Cao T, Liu X, Wang P, Chen M, Yan S, Liu Z, Xiao J, Xu X, Wang Z, Shi Y, Cheong SW, Zhang H, Liang SJ, Miao F. Cascadable in-memory computing based on symmetric writing and readout. Sci Adv 2022; 8:eabq6833. [PMID: 36490344 DOI: 10.1126/sciadv.abq6833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The building block of in-memory computing with spintronic devices is mainly based on the magnetic tunnel junction with perpendicular interfacial anisotropy (p-MTJ). The resulting asymmetric write and readout operations impose challenges in downscaling and direct cascadability of p-MTJ devices. Here, we propose that a previously unimplemented symmetric write and readout mechanism can be realized in perpendicular-anisotropy spin-orbit (PASO) quantum materials based on Fe3GeTe2 and WTe2. We demonstrate that field-free and deterministic reversal of the perpendicular magnetization can be achieved using unconventional charge-to-z-spin conversion. The resulting magnetic state can be readily probed with its intrinsic inverse process, i.e., z-spin-to-charge conversion. Using the PASO quantum material as a fundamental building block, we implement the functionally complete set of logic-in-memory operations and a more complex nonvolatile half-adder logic function. Our work highlights the potential of PASO quantum materials for the development of scalable energy-efficient and ultrafast spintronic computing.
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Affiliation(s)
- Lizheng Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Junlin Xiong
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Bin Cheng
- Institute of Interdisciplinary Physical Sciences, School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yudi Dai
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Fuyi Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chen Pan
- Institute of Interdisciplinary Physical Sciences, School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Tianjun Cao
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaowei Liu
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Pengfei Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Moyu Chen
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Shengnan Yan
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zenglin Liu
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jingjing Xiao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xianghan Xu
- Center for Quantum Materials Synthesis, and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Zhenlin Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Youguo Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sang-Wook Cheong
- Center for Quantum Materials Synthesis, and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Haijun Zhang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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15
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Cheong SW, Huang FT, Kim M. Linking emergent phenomena and broken symmetries through one-dimensional objects and their dot/cross products. Rep Prog Phys 2022; 85:124501. [PMID: 36198263 DOI: 10.1088/1361-6633/ac97aa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
The symmetry of the whole experimental setups, including specific sample environments and measurables, can be compared with that of specimens for observable physical phenomena. We, first, focus on one-dimensional (1D) experimental setups, independent from any spatial rotation around one direction, and show that eight kinds of 1D objects (four; vector-like, the other four; director-like), defined in terms of symmetry, and their dot and cross products are an effective way for the symmetry consideration. The dot products form a Z2× Z2× Z2group with Abelian additive operation, and the cross products form a Z2× Z2group with Abelian additive operation or Q8, a non-Abelian group of order eight, depending on their signs. Those 1D objects are associated with characteristic physical phenomena. When a 3D specimen has symmetry operational similarity (SOS) with (identical or lower, but not higher, symmetries than) an 1D object with a particular phenomenon, the 3D specimen can exhibit the phenomenon. This SOS approach can be a transformative and unconventional avenue for symmetry-guided materials designs and discoveries.
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Affiliation(s)
- Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Rd, Piscataway, NJ, United States of America
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Rd, Piscataway, NJ, United States of America
| | - Minhyong Kim
- International Centre for Mathematical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- The Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul, Republic of Korea
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16
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Yang H, Konečná A, Xu X, Cheong SW, Batson PE, García de Abajo FJ, Garfunkel E. Simultaneous Imaging of Dopants and Free Charge Carriers by Monochromated EELS. ACS Nano 2022; 16:18795-18805. [PMID: 36317944 DOI: 10.1021/acsnano.2c07540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Doping inhomogeneities in solids are not uncommon, but their microscopic observation and understanding are limited due to the lack of bulk-sensitive experimental techniques with high enough spatial and spectral resolution. Here, we demonstrate nanoscale imaging of both dopants and free charge carriers in La-doped BaSnO3 (BLSO) using high-resolution electron energy-loss spectroscopy (EELS). By analyzing high- and low-energy excitations in EELS, we reveal chemical and electronic inhomogeneities within a single BLSO nanocrystal. The inhomogeneous doping leads to distinctive localized infrared surface plasmons, including a previously unobserved plasmon mode that is highly confined between high- and low-doping regions. We further quantify the carrier density, effective mass, and dopant activation percentage by EELS and transport measurements on the bulk single crystals of BLSO. These results not only represent a practical approach for studying heterogeneities in solids and understanding structure-property relationships at the nanoscale, but also demonstrate the possibility of infrared plasmon tuning by leveraging nanoscale doping texture.
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Affiliation(s)
- Hongbin Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey08854, United States
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- Central European Institute of Technology, Brno University of Technology, 61200Brno, Czech Republic
| | - Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - Philip E Batson
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860Castelldefels, Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010Barcelona, Spain
| | - Eric Garfunkel
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey08854, United States
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey08854, United States
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17
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Xu X, Huang FT, Du K, Cheong SW. Multifunctionality of Li 2 SrNb 2 O 7 : Memristivity, Tunable Rectification, Ferroelasticity, and Ferroelectricity. Adv Mater 2022; 34:e2206022. [PMID: 36059043 DOI: 10.1002/adma.202206022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Layered Li2 SrNb2 O7 , an inorganic oxide in its bulk single-crystalline form, is experimentally demonstrated to exhibit multiple structural facets such as ferroelasticity, ferroelectricity, and antiferroelectricity. The transition from a room temperature (RT) centrosymmetric structure to a low-temperature out-of-plane ferroelectric and in-plane antiferroelectric structure and the low-temperature (LT) ferroelectric domain configuration are unveiled in TEM, piezoresponse force microscopy, and polarization loop studies. Li2 SrNb2 O7 also exhibits highly tunable ferroelasticity and excellent Li+ in-plane conduction, which leads to a giant in-plane memristor behavior and an in-plane electronic conductivity increase by three orders of magnitude by electric poling at room RT). The accumulation of Li+ vacancies at the crystal-electrode interface is visualized using in situ optical microscopy. The Li-ionic biased state shows a clear in-plane rectification effect combined with a significant relaxation upon time at RT. Relaxation can be fully suppressed at LTs such as 200 K, and utilizing an electric field cooling, a stable rectification can be achieved at 200 K. The results shed light on the selective control of multifunctionalities such as ferroelasticity, ferroelectricity, and ionic-migration-mediated effects (a memristor effect and rectification) in a single-phase bulk material utilizing, for example, different directions, temperatures, frequencies, and magnitudes of electric field.
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Affiliation(s)
- Xianghan Xu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kai Du
- 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
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18
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Kim MG, Barbour A, Hu W, Wilkins SB, Robinson IK, Dean MPM, Yang J, Won C, Cheong SW, Mazzoli C, Kiryukhin V. Real-space observation of fluctuating antiferromagnetic domains. Sci Adv 2022; 8:eabj9493. [PMID: 35622920 PMCID: PMC9140973 DOI: 10.1126/sciadv.abj9493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
Magnetic domains play a fundamental role in physics of magnetism and its technological applications. Dynamics of antiferromagnetic domains is poorly understood, although antiferromagnets are expected to be extensively used in future electronic devices wherein it determines the stability and operational speed. Dynamics of antiferromagnets also features prominently in the studies of topological quantum matter. Real-space imaging of fluctuating antiferromagnetic domains is therefore highly desired but has never been demonstrated. We use coherent x-ray diffraction to obtain videos of fluctuating micrometer-scale antiferromagnetic domains in Ni2MnTeO6 on time scales from 10-1 to 103 s. In the collinear phase, thermally activated domain wall motion is observed in the vicinity of the Néel temperature. Unexpectedly, the fluctuations persist through the full range of the higher-temperature helical phase. These observations illustrate the high potential significance of the dynamic domain imaging in phase transition studies and in magnetic device research.
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Affiliation(s)
- Min Gyu Kim
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - Andi Barbour
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Wen Hu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Stuart B. Wilkins
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Ian K. Robinson
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Mark P. M. Dean
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Choongjae Won
- Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technology, Pohang 37673, Korea
- Laboratory of Pohang Emergent Materials, Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
- Max Planck POSTECH/Korea Research Initiative, Pohang University of Science and Technology, Pohang 37673, Korea
- Laboratory of Pohang Emergent Materials, Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854, USA
| | - Claudio Mazzoli
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Valery Kiryukhin
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
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19
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Yang H, Konečná A, Xu X, Cheong SW, Garfunkel E, García de Abajo FJ, Batson PE. Low-Loss Tunable Infrared Plasmons in the High-Mobility Perovskite (Ba,La)SnO 3. Small 2022; 18:e2106897. [PMID: 35279954 DOI: 10.1002/smll.202106897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/06/2022] [Indexed: 06/14/2023]
Abstract
BaSnO3 exhibits the highest carrier mobility among perovskite oxides, making it ideal for oxide electronics. Collective charge carrier oscillations known as plasmons are expected to arise in this material, thus providing a tool to control the nanoscale optical field for optoelectronics applications. Here, the existence of relatively long-lived plasmons supported by high-mobility charge carriers in La-doped BaSnO3 (BLSO) is demonstrated. By exploiting the high spatial and energy resolution of electron energy-loss spectroscopy with a focused beam in a scanning transmission electron microscope, the dispersion, confinement ratio, and damping of infrared localized surface plasmons (LSPs) in BLSO nanoparticles are systematically investigated. It is found that LSPs in BLSO exhibit a high degree of spatial confinement compared to those sustained by noble metals and have relatively low losses and high quality factors with respect to other doped oxides. Further analysis clarifies the relation between plasmon damping and carrier mobility in BLSO. The results support the use of nanostructured degenerate semiconductors for plasmonic applications in the infrared region and establish a solid alternative to more traditional plasmonic materials.
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Affiliation(s)
- Hongbin Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- Central European Institute of Technology, Brno University of Technology, Brno, 61200, Czech Republic
| | - Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Eric Garfunkel
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Philip E Batson
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
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20
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Lim S, Pan S, Wang K, Ushakov AV, Sukhanova EV, Popov ZI, Kvashnin DG, Streltsov SV, Cheong SW. Tunable Single-Atomic Charges on a Cleaved Intercalated Transition Metal Dichalcogenide. Nano Lett 2022; 22:1812-1817. [PMID: 34890208 DOI: 10.1021/acs.nanolett.1c03706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Control of a single ionic charge state by altering the number of bound electrons has been considered as an ultimate testbed for atomic charge-induced interactions and manipulations, and such subject has been studied in artificially deposited objects on thin insulating layers. We demonstrate that an entire layer of controllable atomic charges on a periodic lattice can be obtained by cleaving metallic Co1/3NbS2, an intercalated transition metal dichalcogenide. We identified a metastable charge state of Co with a different valence and manipulated atomic charges to form a linear chain of the metastable charge state. Density functional theory investigation reveals that the charge state is stable due to a modified crystal field at the surface despite the coupling between NbS2 and Co via a1g orbitals. The idea can be generalized to other combinations of intercalants and base matrices, suggesting that they can be a new platform to explore single-atom-operational 2D electronics/spintronics.
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Affiliation(s)
- Seongjoon Lim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Shangke Pan
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers The State University of New Jersey, Piscataway, New Jersey 08854, United States
- State Key Laboratory Base of Novel Function Materials and Preparation Science, School of Material Sciences and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Kefeng Wang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Alexey V Ushakov
- Institute of Metal Physics, S. Kovalevskaya Street 18, Yekaterinburg 620108, Russia
| | - Ekaterina V Sukhanova
- Emanuel Institute of Biochemical Physics of RAS, 4 Kosygin Street, 119334, Moscow, Russia
| | - Zakhar I Popov
- Emanuel Institute of Biochemical Physics of RAS, 4 Kosygin Street, 119334, Moscow, Russia
- Plekhanov Russian University of Economics, 36 Stremyanny per., 117997, Moscow, Russia
| | - Dmitry G Kvashnin
- Emanuel Institute of Biochemical Physics of RAS, 4 Kosygin Street, 119334, Moscow, Russia
- Moscow Institute of Physics and Technology (State University), 9 Institutskiy per., 141701, Dolgoprudny, Moscow Region, Russia
| | - Sergey V Streltsov
- Institute of Metal Physics, S. Kovalevskaya Street 18, Yekaterinburg 620108, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira Street 19, Yekaterinburg 620002, Russia
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers The State University of New Jersey, Piscataway, New Jersey 08854, United States
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21
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Seo J, De C, Ha H, Lee JE, Park S, Park J, Skourski Y, Choi ES, Kim B, Cho GY, Yeom HW, Cheong SW, Kim JH, Yang BJ, Kim K, Kim JS. Colossal angular magnetoresistance in ferrimagnetic nodal-line semiconductors. Nature 2021; 599:576-581. [PMID: 34819684 DOI: 10.1038/s41586-021-04028-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 09/15/2021] [Indexed: 11/09/2022]
Abstract
Efficient magnetic control of electronic conduction is at the heart of spintronic functionality for memory and logic applications1,2. Magnets with topological band crossings serve as a good material platform for such control, because their topological band degeneracy can be readily tuned by spin configurations, dramatically modulating electronic conduction3-10. Here we propose that the topological nodal-line degeneracy of spin-polarized bands in magnetic semiconductors induces an extremely large angular response of magnetotransport. Taking a layered ferrimagnet, Mn3Si2Te6, and its derived compounds as a model system, we show that the topological band degeneracy, driven by chiral molecular orbital states, is lifted depending on spin orientation, which leads to a metal-insulator transition in the same ferrimagnetic phase. The resulting variation of angular magnetoresistance with rotating magnetization exceeds a trillion per cent per radian, which we call colossal angular magnetoresistance. Our findings demonstrate that magnetic nodal-line semiconductors are a promising platform for realizing extremely sensitive spin- and orbital-dependent functionalities.
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Affiliation(s)
- Junho Seo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Chandan De
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Laboratory of Pohang Emergent Materials, Pohang Accelerator Laboratory, Pohang, Korea
| | - Hyunsoo Ha
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Ji Eun Lee
- Department of Physics, Yonsei University, Seoul, Korea
| | - Sungyu Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea
| | - Joonbum Park
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Yurii Skourski
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Eun Sang Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - Bongjae Kim
- Department of Physics, Kunsan National University, Gunsan, Korea
| | - Gil Young Cho
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea.,Asia Pacific Center for Theoretical Physics, Pohang, Korea
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea
| | - Sang-Wook Cheong
- Laboratory of Pohang Emergent Materials, Pohang Accelerator Laboratory, Pohang, Korea.,Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Jae Hoon Kim
- Department of Physics, Yonsei University, Seoul, Korea.
| | - Bohm-Jung Yang
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea. .,Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Korea. .,Center for Theoretical Physics (CTP), Seoul National University, Seoul, Korea.
| | - Kyoo Kim
- Korea Atomic Energy Research Institute (KAERI), Daejeon, Korea.
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
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22
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Giri A, De C, Kumar M, Pal M, Lee HH, Kim JS, Cheong SW, Jeong U. Large-Area Epitaxial Film Growth of van der Waals Ferromagnetic Ternary Chalcogenides. Adv Mater 2021; 33:e2103609. [PMID: 34536038 DOI: 10.1002/adma.202103609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/03/2021] [Indexed: 06/13/2023]
Abstract
Following the first experimental realization of intrinsic ferromagnetism in 2D van der Waals (vdW) crystals, several ternary metal chalcogenides with unprecedented long-range ferromagnetic order have been explored. However, the synthesis of large-area 2D ternary metal chalcogenide thin films is a great challenge, and a generalized synthesis has not been demonstrated yet. Here, a quick and scalable synthesis of epitaxially aligned ferromagnetic ternary metal chalcogenide thin films (Cr2 Ge2 Te6 , Cr2 Si2 Te6 , Mn3 Si2 Te6 ) is reported. The synthesis is based on the flux-controlled surface diffusion of Te on metal (Cr, Mn)-deposited wafer (Ge, Si) substrates. Magnetic anisotropy study of the epitaxial ternary thin films reveals the intrinsic magnetic easy axis; out-of-plane direction for Cr2 Ge2 Te6 and Cr2 Si2 Te6 , and in-plane direction for Mn3 Si2 Te6 . In addition to the synthesis, this work creates an opportunity for transfer-free device fabrication for realizing magnetoelectronics based on the electrical control of both charge and spin degrees of freedom in 2D ferromagnetic semiconductors.
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Affiliation(s)
- Anupam Giri
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
| | - Chandan De
- Center for Artificial Low Dimensional Electronic System (CALDES), Institute for Basic Science (IBS), Pohang, Republic of Korea
- Laboratory of Pohang Emergent Materials (l-PEM), Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
| | - Manish Kumar
- Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
| | - Monalisa Pal
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Hyun Hwi Lee
- Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
| | - Jun Sung Kim
- Center for Artificial Low Dimensional Electronic System (CALDES), Institute for Basic Science (IBS), Pohang, Republic of Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Sang-Wook Cheong
- Laboratory of Pohang Emergent Materials (l-PEM), Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey, 08854, USA
| | - Unyong Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 790-784, Korea
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23
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Luo X, Obeysekera D, Won C, Sung SH, Schnitzer N, Hovden R, Cheong SW, Yang J, Sun K, Zhao L. Ultrafast Modulations and Detection of a Ferro-Rotational Charge Density Wave Using Time-Resolved Electric Quadrupole Second Harmonic Generation. Phys Rev Lett 2021; 127:126401. [PMID: 34597104 DOI: 10.1103/physrevlett.127.126401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/04/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
We show the ferro-rotational nature of the commensurate charge density wave (CCDW) in 1T-TaS_{2} and track its dynamic modulations by temperature-dependent and time-resolved electric quadrupole rotation anisotropy-second harmonic generation (EQ RA-SHG), respectively. The ultrafast modulations manifest as the breathing and the rotation of the EQ RA-SHG patterns at three frequencies around the reported single CCDW amplitude mode frequency. A sudden shift of the triplet frequencies and a dramatic increase in the breathing and rotation magnitude further reveal a photoinduced transient CDW phase across a critical pump fluence of ∼0.5 mJ/cm^{2}.
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Affiliation(s)
- Xiangpeng Luo
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
| | - Dimuthu Obeysekera
- Department of Physics, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, New Jersey 07102, USA
| | - Choongjae Won
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Suk Hyun Sung
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Noah Schnitzer
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Robert Hovden
- Department of Materials Sciences, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, USA
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, 323 Dr Martin Luther King Jr Blvd, Newark, New Jersey 07102, USA
| | - Kai Sun
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
| | - Liuyan Zhao
- Department of Physics, University of Michigan, 450 Church St, Ann Arbor, Michigan 48109, USA
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24
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Ding L, Xu X, Jeschke HO, Bai X, Feng E, Alemayehu AS, Kim J, Huang FT, Zhang Q, Ding X, Harrison N, Zapf V, Khomskii D, Mazin II, Cheong SW, Cao H. Field-tunable toroidal moment in a chiral-lattice magnet. Nat Commun 2021; 12:5339. [PMID: 34504085 PMCID: PMC8429646 DOI: 10.1038/s41467-021-25657-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/17/2021] [Indexed: 11/17/2022] Open
Abstract
Ferrotoroidal order, which represents a spontaneous arrangement of toroidal moments, has recently been found in a few linear magnetoelectric materials. However, tuning toroidal moments in these materials is challenging. Here, we report switching between ferritoroidal and ferrotoroidal phases by a small magnetic field, in a chiral triangular-lattice magnet BaCoSiO4 with tri-spin vortices. Upon applying a magnetic field, we observe multi-stair metamagnetic transitions, characterized by equidistant steps in the net magnetic and toroidal moments. This highly unusual ferri-ferroic order appears to come as a result of an unusual hierarchy of frustrated isotropic exchange couplings revealed by first principle calculations, and the antisymmetric exchange interactions driven by the structural chirality. In contrast to the previously known toroidal materials identified via a linear magnetoelectric effect, BaCoSiO4 is a qualitatively new multiferroic with an unusual coupling between several different orders, and opens up new avenues for realizing easily tunable toroidal orders. Toroidal moments arise from vortex like spin arrangements. These moments can then interact, giving rise to ferri- or ferro-toroidal order, though controlling such order is difficult. Here, the authors demonstrate a ferri-toroidal state in BaCoSiO4, which under an applied magnetic field exhibits multiple toroidal and metamagnetic transitions.
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Affiliation(s)
- Lei Ding
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN, USA
| | - Xianghan Xu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA
| | - Harald O Jeschke
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
| | - Xiaojian Bai
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN, USA
| | - Erxi Feng
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN, USA
| | - Admasu Solomon Alemayehu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA
| | - Jaewook Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA
| | - Qiang Zhang
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN, USA
| | - Xiaxin Ding
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Neil Harrison
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Vivien Zapf
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Daniel Khomskii
- II. Physikalisches Institut, Universität zu Köln, Köln, Germany
| | - Igor I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, USA.
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, NJ, USA.
| | - Huibo Cao
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, TN, USA.
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25
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Feng E, Samarakoon A, Xu X, Hu C, Liu Y, Tenant A, Ni N, Cheong SW, Cao H. Magnetic vortices in a square lattice revealed by local magnetic susceptibilities and neutron diffuse scattering. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321098925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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26
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Altvater MA, Tilak N, Rao S, Li G, Won CJ, Cheong SW, Andrei EY. Charge Density Wave Vortex Lattice Observed in Graphene-Passivated 1T-TaS 2 by Ambient Scanning Tunneling Microscopy. Nano Lett 2021; 21:6132-6138. [PMID: 34231367 DOI: 10.1021/acs.nanolett.1c01655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The nearly commensurate charge density wave (CDW) excitations native to the transition-metal dichalcogenide crystal, 1T-TaS2, under ambient conditions are revealed by scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of a graphene/TaS2 heterostructure. Surface potential measurements show that the graphene passivation layer prevents oxidation of the air-sensitive 1T-TaS2 surface. The graphene protective layer does not however interfere with probing the native electronic properties of 1T-TaS2 by STM/STS, which revealed that nearly commensurate CDW hosts an array of vortex-like topological defects. We find that these topological defects organize themselves to form a lattice with quasi-long-range order, analogous to the vortex Bragg glass in type-II superconductors but accessible in ambient conditions.
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Affiliation(s)
- Michael A Altvater
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Nikhil Tilak
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Skandaprasad Rao
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Guohong Li
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Choong-Jae Won
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Center for Quantum Materials Synthesis, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Eva Y Andrei
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
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27
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Xu X, Huang FT, Qi Y, Singh S, Rabe KM, Obeysekera D, Yang J, Chu MW, Cheong SW. Kinetically stabilized ferroelectricity in bulk single-crystalline HfO 2:Y. Nat Mater 2021; 20:826-832. [PMID: 33495629 DOI: 10.1038/s41563-020-00897-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 12/02/2020] [Indexed: 05/27/2023]
Abstract
HfO2, a simple binary oxide, exhibits ultra-scalable ferroelectricity integrable into silicon technology. This material has a polymorphic nature, with the polar orthorhombic (Pbc21) form in ultrathin films regarded as the plausible cause of ferroelectricity but thought not to be attainable in bulk crystals. Here, using a state-of-the-art laser-diode-heated floating zone technique, we report the Pbc21 phase and ferroelectricity in bulk single-crystalline HfO2:Y as well as the presence of the antipolar Pbca phase at different Y concentrations. Neutron diffraction and atomic imaging demonstrate (anti)polar crystallographic signatures and abundant 90°/180° ferroelectric domains in addition to switchable polarization with negligible wake-up effects. Density-functional-theory calculations indicate that the yttrium doping and rapid cooling are the key factors for stabilization of the desired phase in bulk. Our observations provide insights into the polymorphic nature and phase control of HfO2, remove the upper size limit for ferroelectricity and suggest directions towards next-generation ferroelectric devices.
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Affiliation(s)
- Xianghan Xu
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Fei-Ting Huang
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Yubo Qi
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Sobhit Singh
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Karin M Rabe
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Dimuthu Obeysekera
- Department of Physics, New Jersey Institute of Technology, Newark, NJ, USA
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, Newark, NJ, USA
| | - Ming-Wen Chu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, Taiwan
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA.
- Department of Physics & Astronomy, Rutgers University, Piscataway, NJ, USA.
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28
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Fan S, Neal S, Won C, Kim J, Sapkota D, Huang F, Yang J, Mandrus DG, Cheong SW, Haraldsen JT, Musfeldt JL. Excitations of Intercalated Metal Monolayers in Transition Metal Dichalcogenides. Nano Lett 2021; 21:99-106. [PMID: 33264028 DOI: 10.1021/acs.nanolett.0c03292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We combine Raman scattering spectroscopy and lattice dynamics calculations to reveal the fundamental excitations of the intercalated metal monolayers in the FexTaS2 (x = 1/4, 1/3) family of materials. Both in- and out-of-plane modes are identified, each of which has trends that depend upon the metal-metal distance, the size of the van der Waals gap, and the metal-to-chalcogenide slab mass ratio. We test these trends against the response of similar systems, including Cr-intercalated NbS2 and RbFe(SO4)2, and demonstrate that the metal monolayer excitations are both coherent and tunable. We discuss the consequences of intercalated metal monolayer excitations for material properties and developing applications.
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Affiliation(s)
- Shiyu Fan
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Sabine Neal
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Choongjae Won
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jaewook Kim
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, United States
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Deepak Sapkota
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Feiting Huang
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Junjie Yang
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - David G Mandrus
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Jason T Haraldsen
- Department of Physics, University of North Florida, Jacksonville, Florida 32224, United States
| | - Janice L Musfeldt
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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29
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Qi Y, Singh S, Lau C, Huang FT, Xu X, Walker FJ, Ahn CH, Cheong SW, Rabe KM. Stabilization of Competing Ferroelectric Phases of HfO_{2} under Epitaxial Strain. Phys Rev Lett 2020; 125:257603. [PMID: 33416369 DOI: 10.1103/physrevlett.125.257603] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 08/25/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Hafnia (HfO_{2})-based thin films have promising applications in nanoscale electronic devices due to their robust ferroelectricity and integration with silicon. Identifying and stabilizing the ferroelectric phases of HfO_{2} have attracted intensive research interest in recent years. In this work, first-principles calculations on (111)-oriented HfO_{2} are used to discover that imposing an in-plane shear strain on the metastable tetragonal phase drives it to a polar phase. This in-plane-shear-induced polar phase is shown to be an epitaxial-strain-induced distortion of a previously proposed metastable ferroelectric Pnm2_{1} phase of HfO_{2}. This ferroelectric Pnm2_{1} phase can account for the recently observed ferroelectricity in (111)-oriented HfO_{2}-based thin films on a SrTiO_{3} (STO) (001) substrate [Nat. Mater. 17, 1095 (2018)NMAACR1476-112210.1038/s41563-018-0196-0]. Further investigation of this alternative ferroelectric phase of HfO_{2} could potentially improve the performances of HfO_{2}-based films in logic and memory devices.
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Affiliation(s)
- Yubo Qi
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Sobhit Singh
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Claudia Lau
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Fei-Ting Huang
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Xianghan Xu
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Frederick J Walker
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Charles H Ahn
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Sang-Wook Cheong
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Karin M Rabe
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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30
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Wang Y, Wang C, Liang SJ, Ma Z, Xu K, Liu X, Zhang L, Admasu AS, Cheong SW, Wang L, Chen M, Liu Z, Cheng B, Ji W, Miao F. Strain-Sensitive Magnetization Reversal of a van der Waals Magnet. Adv Mater 2020; 32:e2004533. [PMID: 32924236 DOI: 10.1002/adma.202004533] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/08/2020] [Indexed: 06/11/2023]
Abstract
By virtue of the layered structure, van der Waals (vdW) magnets are sensitive to the lattice deformation controlled by the external strain, providing an ideal platform to explore the one-step magnetization reversal that is still conceptual in conventional magnets due to the limited strain-tuning range of the coercive field. In this study, a uniaxial tensile strain is applied to thin flakes of the vdW magnet Fe3 GeTe2 (FGT), and a dramatic increase of the coercive field (Hc ) by more than 150% with an applied strain of 0.32% is observed. Moreover, the change of the transition temperatures between the different magnetic phases under strain is investigated, and the phase diagram of FGT in the strain-temperature plane is obtained. Comparing the phase diagram with theoretical results, the strain-tunable magnetism is attributed to the sensitive change of magnetic anisotropy energy. Remarkably, strain allows an ultrasensitive magnetization reversal to be achieved, which may promote the development of novel straintronic device applications.
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Affiliation(s)
- Yu Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Cong Wang
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, P. R. China
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zecheng Ma
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Kang Xu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Xiaowei Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Lili Zhang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Alemayehu S Admasu
- Center for Quantum Materials Synthesis, and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Sang-Wook Cheong
- Center for Quantum Materials Synthesis, and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Lizheng Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Moyu Chen
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zenglin Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Bin Cheng
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, P. R. China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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31
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Lee J, Jin KH, Catuneanu A, Go A, Jung J, Won C, Cheong SW, Kim J, Liu F, Kee HY, Yeom HW. Honeycomb-Lattice Mott Insulator on Tantalum Disulphide. Phys Rev Lett 2020; 125:096403. [PMID: 32915631 DOI: 10.1103/physrevlett.125.096403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Effects of electron many-body interactions amplify in an electronic system with a narrow bandwidth opening a way to exotic physics. A narrow band in a two-dimensional (2D) honeycomb lattice is particularly intriguing as combined with Dirac bands and topological properties but the material realization of a strongly interacting honeycomb lattice described by the Kane-Mele-Hubbard model has not been identified. Here we report a novel approach to realize a 2D honeycomb-lattice narrow-band system with strongly interacting 5d electrons. We engineer a well-known triangular lattice 2D Mott insulator 1T-TaS_{2} into a honeycomb lattice utilizing an adsorbate superstructure. Potassium (K) adatoms at an optimum coverage deplete one-third of the unpaired d electrons and the remaining electrons form a honeycomb lattice with a very small hopping. Ab initio calculations show extremely narrow Z_{2} topological bands mimicking the Kane-Mele model. Electron spectroscopy detects an order of magnitude bigger charge gap confirming the substantial electron correlation as confirmed by dynamical mean field theory. It could be the first artificial Mott insulator with a finite spin Chern number.
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Affiliation(s)
- Jinwon Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Andrei Catuneanu
- Department of Physics, University of Toronto, Ontario M5S 1A7, Canada
| | - Ara Go
- Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea
| | - Jiwon Jung
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Choongjae Won
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Jaeyoung Kim
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Hae-Young Kee
- Department of Physics, University of Toronto, Ontario M5S 1A7, Canada
- Canadian Institute for Advanced Research, CIFAR Program in Quantum Materials, Toronto, Ontario M5G 1M1, Canada
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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32
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Lim S, Kim J, Won C, Cheong SW. Atomic-Scale Observation of Topological Vortices in the Incommensurate Charge Density Wave of 2H-TaSe 2. Nano Lett 2020; 20:4801-4808. [PMID: 32496066 DOI: 10.1021/acs.nanolett.0c00539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
It has been only recently realized that topological vortices associated with structural distortions or ordered spins are rather common in numerous materials where long-range interactions are not dominant. Incommensurate modulations that frequently occur in charge density wave (CDW) materials are often understood in terms of discommensurations with a periodic phase shift. The accumulation of a one-dimensional (1D) phase shift can result in, for example, CDW dislocations in 2H-TaSe2 with incommensurate CDW (I-CDW). Since any atomic-scale experimental investigation of CDW dislocations in 2H-TaSe2 has been lacking, we have performed the atomic-scale observation of 2H-TaSe2 with I-CDW, stabilized with Pd intercalation or strain, with scanning probe microscopy, and unveiled the existence of topological Z6 or Z4 vortices with topologically protected 2D winding movements of atomic displacement vectors. The discovery opens the ubiquitous nature of topological vortex domains and a new avenue to explore new facets of various incommensurate modulations or discommensurations.
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Affiliation(s)
- Seongjoon Lim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, United States
| | - Jaewook Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, United States
| | - Choongjae Won
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH/KOREA Research Initiative, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, United States
- Laboratory for Pohang Emergent Materials, Pohang Accelerator Laboratory and Max Plank POSTECH/KOREA Research Initiative, Pohang University of Science and Technology, Pohang 37673, Korea
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33
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Wu M, Zhou X, Croft M, Ehrlich S, Khalid S, Wen W, Lapidus SH, Xu X, Li MR, Liu Z, Cheong SW. Single-Crystal Growth and Room-Temperature Magnetocaloric Effect of X-Type Hexaferrite Sr 2Co 2Fe 28O 46. Inorg Chem 2020; 59:6755-6762. [PMID: 32364708 DOI: 10.1021/acs.inorgchem.9b03724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
X-type hexaferrites have been receiving considerable attention due to their promising applications in many magnetic-electronic fields. However, the growth of single-crystal X-type hexaferrite is still a challenge. Herein we reported, for the first time, the preparation of single crystal X-type hexaferrite Sr2Co2Fe28O46 (Sr2Co2X) with high-quality and large size using floating-zone method with laser as the heating source. The crystals show rhombohedral symmetry with space group of R-3m (No. 166, a = 5.8935(1) Å and c = 83.7438(17) Å). Co2+ and Fe3+ oxidation states were confirmed by the X-ray absorption near-edge spectroscopy. The prepared Sr2Co2X exhibits a spin reorientation transition from easy-cone to easy-axis at T2 of 343 K and a ferrimagnetism-paramagnetism transition at Curie temperature (TC) of ∼743 K. The spin reorientation transition was accompanied by magnetocaloric effect (MCE). Both conventional and inverse MCEs were observed near T2 with a magnetic field applied along the c-axis. The maximum value of the magnetic entropy change along the c-axis was evaluated to be 1.1 J/kg·K for a magnetic field change of 5 T.
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Affiliation(s)
- Meixia Wu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China.,Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States.,School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Xiang Zhou
- Research Center of Materials Science and Engineering, Guangxi University of Science and Technology, Liuzhou 545006, PR China
| | - Mark Croft
- Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, United States
| | - Steven Ehrlich
- NSLS-II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Syed Khalid
- NSLS-II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wen Wen
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China.,Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Saul H Lapidus
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Xianghan Xu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Man-Rong Li
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China
| | - Zhongwu Liu
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
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34
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Xiao S, Jin Y, Lu X, Cheong SW, Li J, Li Y, Huang F, Zhu J. Dynamics and manipulation of ferroelectric domain walls in bismuth ferrite thin films. Natl Sci Rev 2020; 7:278-284. [PMID: 34692043 PMCID: PMC8288939 DOI: 10.1093/nsr/nwz176] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/19/2019] [Accepted: 10/25/2019] [Indexed: 11/13/2022] Open
Abstract
Ferroelectric domain walls differ from domains not only in their crystalline and discrete symmetry, but also in their electronic, magnetic, and mechanical properties. Although domain walls provide a degree of freedom to regulate the physical properties at the nanoscale, the relatively lower controllability prevents their practical applications in nano-devices. In this work, with the advantages of 3D domain configuration detection based on piezoresponse force microscopy, we find that the mobility of three types of domain walls (tail-to-tail, head-to-tail, head-to-head) in (001) BiFeO3 films varies with the applied electrical field. Under low voltages, head-to-tail domain walls are more mobile than other domain walls, while, under high voltages, tail-to-tail domain walls become rather active and possess relatively long average lengths. This is due to the high nucleation energy and relatively low growth energy for charged domain walls. Finally, we demonstrate the manipulation of domain walls through successive electric writings, resulting in well-aligned conduction paths as designed, paving the way for their application in advanced spintronic, memory and communication nano-devices.
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Affiliation(s)
- Shuyu Xiao
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Yaming Jin
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Xiaomei Lu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - Jiangyu Li
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.,Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Yang Li
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
| | - Fengzhen Huang
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jinsong Zhu
- National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093, China
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35
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Pal S, Kumar K, Sharma R, Banerjee A, Roy SB, Park JG, Nigam AK, Cheong SW. Possible glass-like random singlet magnetic state in 1T-TaS 2. J Phys Condens Matter 2020; 32:035601. [PMID: 31561241 DOI: 10.1088/1361-648x/ab48be] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two-dimensional layered transition-metal-dichalcogenide compound 1T-TaS2 shows the rare coexistence of charge density wave (CDW) and electron correlation driven Mott transition. In addition, atomic-cluster spins on the triangular lattice of the CDW state of 1T-TaS2 give rise to the possibility of the exotic spin-singlet state in which quantum fluctuations of spins are strong enough to prevent any long range magnetic ordering down to the temperature absolute zero (0 K). We present here the evidences of a glass-like random singlet magnetic state in 1T-TaS2 at low temperatures through a study of temperature and time dependence of magnetization. Comparing the experimental results with a representative canonical spin-glass system Au(1.8%Mn), we show that this glass-like state is distinctly different from the well established canonical spin-glass state.
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Affiliation(s)
- Sudip Pal
- UGC DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, India
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36
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Huang FT, Joon Lim S, Singh S, Kim J, Zhang L, Kim JW, Chu MW, Rabe KM, Vanderbilt D, Cheong SW. Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe 2. Nat Commun 2019; 10:4211. [PMID: 31527602 PMCID: PMC6746811 DOI: 10.1038/s41467-019-11949-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 08/13/2019] [Indexed: 11/09/2022] Open
Abstract
Much of the dramatic growth in research on topological materials has focused on topologically protected surface states. While the domain walls of topological materials such as Weyl semimetals with broken inversion or time-reversal symmetry can provide a hunting ground for exploring topological interfacial states, such investigations have received little attention to date. Here, utilizing in-situ cryogenic transmission electron microscopy combined with first-principles calculations, we discover intriguing domain-wall structures in MoTe2, both between polar variants of the low-temperature(T) Weyl phase, and between this and the high-T higher-order topological phase. We demonstrate how polar domain walls can be manipulated with electron beams and show that phase domain walls tend to form superlattice-like structures along the c axis. Scanning tunneling microscopy indicates a possible signature of a conducting hinge state at phase domain walls. Our results open avenues for investigating topological interfacial states and unveiling multifunctional aspects of domain walls in topological materials.
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Affiliation(s)
- Fei-Ting Huang
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Seong Joon Lim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Sobhit Singh
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jinwoong Kim
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Lunyong Zhang
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Jae-Wook Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Ming-Wen Chu
- Center for Condensed Matter Sciences and Center of Atomic Initiative for New Materials, National Taiwan University, 106, Taipei, Taiwan
| | - Karin M Rabe
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - David Vanderbilt
- 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.
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37
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Dally RL, Ratcliff WD, Bleuel M, Zhang L, Cheong SW, Lynn JW. Magnetic skyrmion spin texture hosts and detection using small-angle neutron scattering. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319097915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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38
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Yao X, Gao B, Han MG, Jain D, Moon J, Kim JW, Zhu Y, Cheong SW, Oh S. Record High-Proximity-Induced Anomalous Hall Effect in (Bi xSb 1-x) 2Te 3 Thin Film Grown on CrGeTe 3 Substrate. Nano Lett 2019; 19:4567-4573. [PMID: 31185718 DOI: 10.1021/acs.nanolett.9b01495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quantum anomalous Hall effect (QAHE) can only be realized at extremely low temperatures in magnetically doped topological insulators (TIs) due to limitations inherent with the doping process. In an effort to boost the quantization temperature of QAHE, the magnetic proximity effect in magnetic insulator/TI heterostructures has been extensively investigated. However, the observed anomalous Hall resistance has never been more than several ohms, presumably owing to the interfacial disorders caused by the structural and chemical mismatch. Here, we show that, by growing (BixSb1-x)2Te3 (BST) thin films on structurally and chemically well-matched, ferromagnetic-insulating CrGeTe3 (CGT) substrates, the proximity-induced anomalous Hall resistance can be enhanced by more than an order of magnitude. This sheds light on the importance of structural and chemical matches for magnetic insulator/TI proximity systems.
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Affiliation(s)
- Xiong Yao
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Bin Gao
- Department of Physics and Astronomy , Rice University , Houston , Texas 77005 , United States
| | - Myung-Geun Han
- Condensed Matter Physics and Materials Science , Brookhaven National Laboratory , Upton , New York 11973 , United States
| | - Deepti Jain
- Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Jisoo Moon
- Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Jae Wook Kim
- Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science , Brookhaven National Laboratory , Upton , New York 11973 , United States
| | - Sang-Wook Cheong
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Seongshik Oh
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
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39
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40
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Kim DH, Kim K, Ko KT, Seo J, Kim JS, Jang TH, Kim Y, Kim JY, Cheong SW, Park JH. Giant Magnetic Anisotropy Induced by Ligand LS Coupling in Layered Cr Compounds. Phys Rev Lett 2019; 122:207201. [PMID: 31172742 DOI: 10.1103/physrevlett.122.207201] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Indexed: 06/09/2023]
Abstract
We propose a novel origin of magnetic anisotropy to explain the unusual magnetic behaviors of layered ferromagnetic Cr compounds (3d^{3}) wherein the anisotropy field varies from ≲0.01 to ∼3 T on changing the ligand atom in a common hexagonal structure. The effect of the ligand p orbital spin-orbit (LS) coupling on the magnetic anisotropy is explored by using four-site full multiplet cluster model calculations for energies involving the superexchange interaction at different spin axes. Our calculation shows that the anisotropy energy, which is the energy difference for different spin axes, is strongly affected not only by the LS coupling strength but also by the degree of p-d covalency in the layered geometry. This anisotropy energy involving the superexchange appears to dominate the magnetic anisotropy and even explains the giant magnetic anisotropy as large as 3 T observed in CrI_{3}.
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Affiliation(s)
- Dong-Hwan Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - Kyoo Kim
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - Kyung-Tae Ko
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - JunHo Seo
- Department of Physics, POSTECH, Pohang 37673, Korea
- Center for Artificial Low Dimensional Electronic Systems, IBS, Pohang 37673, Korea
| | - Jun Sung Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- Center for Artificial Low Dimensional Electronic Systems, IBS, Pohang 37673, Korea
| | - Tae-Hwan Jang
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - Younghak Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Korea
| | - Jae-Young Kim
- Center for Artificial Low Dimensional Electronic Systems, IBS, Pohang 37673, Korea
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, POSTECH, Pohang 37673, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Jae-Hoon Park
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Division of Advanced Materials Science, POSTECH, Pohang 37673, Korea
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41
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Li Q, Yang M, Gong C, Chopdekar RV, N'Diaye AT, Turner J, Chen G, Scholl A, Shafer P, Arenholz E, Schmid AK, Wang S, Liu K, Gao N, Admasu AS, Cheong SW, Hwang C, Li J, Wang F, Zhang X, Qiu Z. Patterning-Induced Ferromagnetism of Fe 3GeTe 2 van der Waals Materials beyond Room Temperature. Nano Lett 2018; 18:5974-5980. [PMID: 30114354 DOI: 10.1021/acs.nanolett.8b02806] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Magnetic van der Waals (vdW) materials have emerged as promising candidates for spintronics applications, especially after the recent discovery of intrinsic ferromagnetism in monolayer vdW materials. There has been a critical need for tunable ferromagnetic vdW materials beyond room temperature. Here, we report a real-space imaging study of itinerant ferromagnet Fe3GeTe2 and the enhancement of its Curie temperature well above ambient temperature. We find that the magnetic long-range order in Fe3GeTe2 is characterized by an unconventional out-of-plane stripe-domain phase. In Fe3GeTe2 microstructures patterned by a focused ion beam, the out-of-plane stripe domain phase undergoes a surprising transition at 230 K to an in-plane vortex phase that persists beyond room temperature. The discovery of tunable ferromagnetism in Fe3GeTe2 materials opens up vast opportunities for utilizing vdW magnets in room-temperature spintronics devices.
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Affiliation(s)
- Qian Li
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Mengmeng Yang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Cheng Gong
- Nano-Scale Science and Engineering Center (NSEC) , University of California , 3112 Etcheverry Hall , Berkeley , California 94720 , United States
| | | | | | | | - Gong Chen
- Department of Physics , University of California , Davis , California 95616 , United States
| | | | | | | | | | - Sheng Wang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Kai Liu
- Department of Physics , University of California , Davis , California 95616 , United States
- Department of Physics , Georgetown University , Washington , D.C. 20057 , United States
| | - Nan Gao
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Alemayehu S Admasu
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States
| | - Chanyong Hwang
- Korea Research Institute of Standards and Science , Yuseong, Daejeon 305-340 , Republic of Korea
| | - Jia Li
- International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , China
| | - Feng Wang
- Department of Physics , University of California , Berkeley , California 94720 , United States
| | - Xiang Zhang
- Nano-Scale Science and Engineering Center (NSEC) , University of California , 3112 Etcheverry Hall , Berkeley , California 94720 , United States
| | - Ziqiang Qiu
- Department of Physics , University of California , Berkeley , California 94720 , United States
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42
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Gordon EE, Cheng X, Kim J, Cheong SW, Deng S, Whangbo MH. Nonequivalent Spin Exchanges of the Hexagonal Spin Lattice Affecting the Low-Temperature Magnetic Properties of RInO 3 (R = Gd, Tb, Dy): Importance of Spin-Orbit Coupling for Spin Exchanges between Rare-Earth Cations with Nonzero Orbital Moments. Inorg Chem 2018; 57:9260-9265. [PMID: 30036040 DOI: 10.1021/acs.inorgchem.8b01274] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rare-earth indium oxides RInO3 (R = Gd, Tb, Dy) consist of spin-frustrated hexagonal spin lattices made up of rare-earth ions R3+, where R3+ = Gd3+ (f7, L = 0), Tb3+ (f8, L = 3), and Dy3+ (f9, L = 5). We carried out DFT calculations for RInO3, including on-site repulsion U with/without spin-orbit coupling (SOC), to explore if their low-temperature magnetic properties are related to the two nonequivalent nearest-neighbor (NN) spin exchanges of their hexagonal spin lattices. Our DFT + U + SOC calculations predict that the orbital moments of the Tb3+ and Dy3+ ions are smaller than their free-ion values by ∼2μB while the Tb3+ spins have an in-plane magnetic anisotropy, in agreement with the experiments. This suggests that the f orbitals of each R3+ (R = Tb, Dy) ion are engaged, though weakly, in bonding with the surrounding ligand atoms. The magnetic properties of GdInO3 with the zero orbital moment are adequately described by the spin exchanges extracted by DFT + U calculations. In describing the magnetic properties of TbInO3 and DyInO3 with nonzero orbital moments, however, the spin exchanges extracted by DFT + U + SOC calculations are necessary. The spin exchanges of RInO3 (R = Gd, Tb, Dy) are dominated by the two NN spin exchanges J1 and J2 of their hexagonal spin lattice, in which the honeycomb lattice of J2 forms spin-frustrated ( J1, J1, J2) triangles. The J2/ J1 ratios are calculated to be ∼3, ∼1.7, and ∼1 for GdInO3, TbInO3, and DyInO3, respectively. This suggests that the antiferromagnetic (AFM) ordering of GdInO3 below 1.8 K is most likely an AFM ordering of its honeycomb spin lattice and that TbInO3 would exhibit low-temperature magnetic properties similar to those of GdInO3 while DyInO3 would not.
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Affiliation(s)
- Elijah E Gordon
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Xiyue Cheng
- State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS) , Fuzhou 350002 , China
| | - Jaewook Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Shuiquan Deng
- State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS) , Fuzhou 350002 , China
| | - Myung-Hwan Whangbo
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States.,State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS) , Fuzhou 350002 , China.,State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
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43
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Ding X, Chai YS, Balakirev F, Jaime M, Yi HT, Cheong SW, Sun Y, Zapf V. Measurement of the angle dependence of magnetostriction in pulsed magnetic fields using a piezoelectric strain gauge. Rev Sci Instrum 2018; 89:085109. [PMID: 30184619 DOI: 10.1063/1.5038741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/21/2018] [Indexed: 06/08/2023]
Abstract
We present a high resolution method for measuring magnetostriction in millisecond pulsed magnetic fields at cryogenic temperatures with a sensitivity of 1.11×10-11/Hz . The sample is bonded to a thin piezoelectric plate such that when the sample's length changes, it strains the piezoelectric and induces a voltage change. This method is more sensitive than a fiber-Bragg grating method. It measures two axes simultaneously instead of one. The gauge is small and versatile, functioning in DC and millisecond pulsed magnetic fields. We demonstrate its use by measuring the magnetostriction of Ca3Co1.03Mn0.97O6 single crystals in pulsed magnetic fields. By comparing our data to new and previously published results from a fiber-Bragg grating magnetostriction setup, we confirm that this method detects magnetostriction effects. We also demonstrate the small size and versatility of this technique by measuring angle dependence with respect to the applied magnetic field in a rotator probe in 65 T millisecond pulsed magnetic fields.
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Affiliation(s)
- Xiaxin Ding
- National High Magnetic Field Laboratory (NHMFL), Materials Physics and Applications (MPA)-Magnet (MAG) Group, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
| | - Yi-Sheng Chai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Fedor Balakirev
- National High Magnetic Field Laboratory (NHMFL), Materials Physics and Applications (MPA)-Magnet (MAG) Group, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
| | - Marcelo Jaime
- National High Magnetic Field Laboratory (NHMFL), Materials Physics and Applications (MPA)-Magnet (MAG) Group, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
| | - Hee Taek Yi
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Young Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Vivien Zapf
- National High Magnetic Field Laboratory (NHMFL), Materials Physics and Applications (MPA)-Magnet (MAG) Group, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
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44
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Zhang W, Chen M, Dai J, Wang X, Zhong Z, Cheong SW, Wu W. Topological Phase Transition with Nanoscale Inhomogeneity in (Bi 1- xIn x) 2Se 3. Nano Lett 2018; 18:2677-2682. [PMID: 29582663 DOI: 10.1021/acs.nanolett.8b00597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Topological insulators are a class of band insulators with nontrivial topology, a result of band inversion due to the strong spin-orbit coupling. The transition between topological and normal insulator can be realized by tuning the spin-orbit coupling strength and has been observed experimentally. However, the impact of chemical disorders on the topological phase transition was not addressed in previous studies. Herein, we report a systematic scanning tunneling microscopy/spectroscopy and first-principles study of the topological phase transition in single crystals of In-doped Bi2Se3. Surprisingly, no band gap closure was observed across the transition. Furthermore, our spectroscopic-imaging results reveal that In defects are extremely effective "suppressors" of the band inversion, which leads to microscopic phase separation of topological-insulator-like and normal-insulator-like nano regions across the "transition". The observed topological electronic inhomogeneity demonstrates the significant impact of chemical disorders in topological materials, shedding new light on the fundamental understanding of topological phase transition.
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Affiliation(s)
- Wenhan Zhang
- Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Mingxing Chen
- College of Physics and Information Science , Hunan Normal University , Changsha , Hunan 410081 , China
| | - Jixia Dai
- Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Xueyun Wang
- Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
- School of Aerospace Engineering , Beijing Institute of Technology , Beijing 100081 , China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials and Devices , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
| | - Sang-Wook Cheong
- Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
- Rutgers Center for Emergent Materials , Rutgers University , Piscataway , New Jersey 08854 , United States
| | - Weida Wu
- Department of Physics and Astronomy , Rutgers University , Piscataway , New Jersey 08854 , United States
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45
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Yu S, Gao B, Kim JW, Cheong SW, Man MKL, Madéo J, Dani KM, Talbayev D. High-Temperature Terahertz Optical Diode Effect without Magnetic Order in Polar FeZnMo_{3}O_{8}. Phys Rev Lett 2018; 120:037601. [PMID: 29400514 DOI: 10.1103/physrevlett.120.037601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Indexed: 06/07/2023]
Abstract
We present a terahertz spectroscopic study of polar ferrimagnet FeZnMo_{3}O_{8}. Our main finding is a giant high-temperature optical diode effect, or nonreciprocal directional dichroism, where the transmitted light intensity in one direction is over 100 times lower than intensity transmitted in the opposite direction. The effect takes place in the paramagnetic phase with no long-range magnetic order in the crystal, which contrasts sharply with all existing reports of the terahertz optical diode effect in other magnetoelectric materials, where the long-range magnetic ordering is a necessary prerequisite. In FeZnMo_{3}O_{8}, the effect occurs resonantly with a strong magnetic dipole active transition centered at 1.27 THz and assigned as electron spin resonance between the eigenstates of the single-ion anisotropy Hamiltonian. We propose that the optical diode effect in paramagnetic FeZnMo_{3}O_{8} is driven by single-ion terms in magnetoelectric free energy.
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Affiliation(s)
- Shukai Yu
- Department of Physics and Engineering Physics, Tulane University, 6400 Freret St., New Orleans, Louisiana 70118, USA
| | - Bin Gao
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Jae Wook Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Michael K L Man
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Julien Madéo
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Keshav M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Diyar Talbayev
- Department of Physics and Engineering Physics, Tulane University, 6400 Freret St., New Orleans, Louisiana 70118, USA
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46
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Laurita NJ, Luo Y, Hu R, Wu M, Cheong SW, Tchernyshyov O, Armitage NP. Asymmetric Splitting of an Antiferromagnetic Resonance via Quartic Exchange Interactions in Multiferroic Hexagonal HoMnO_{3}. Phys Rev Lett 2017; 119:227601. [PMID: 29286798 DOI: 10.1103/physrevlett.119.227601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Indexed: 06/07/2023]
Abstract
The symmetric splitting of two spin-wave branches in an antiferromagnetic resonance (AFR) experiment has been an essential measurement of antiferromagnets for over half a century. In this work, circularly polarized time-domain THz spectroscopy experiments performed on the low symmetry multiferroic hexagonal HoMnO_{3} reveal an AFR of the Mn sublattice to split asymmetrically in an applied magnetic field, with an ≈50% difference in g factors between the high and low energy branches of this excitation. The temperature dependence of the g factors, including a drastic renormalization at the Ho spin ordering temperature, reveals this asymmetry to unambiguously stem from Ho-Mn interactions. Theoretical calculations demonstrate that the AFR asymmetry is not explained by conventional Ho-Mn exchange mechanisms alone and is only reproduced if quartic spin interactions are also included in the spin Hamiltonian. Our results provide a paradigm for the optical study of such novel interactions in hexagonal manganites and low symmetry antiferromagnets in general.
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Affiliation(s)
- N J Laurita
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yi Luo
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Rongwei Hu
- Rutgers Center For Emergent Materials, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Meixia Wu
- Rutgers Center For Emergent Materials, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - S W Cheong
- Rutgers Center For Emergent Materials, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - O Tchernyshyov
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - N P Armitage
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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47
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Choi S, Choi HJ, Ok JM, Lee Y, Jang WJ, Lee AT, Kuk Y, Lee S, Heinrich AJ, Cheong SW, Bang Y, Johnston S, Kim JS, Lee J. Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor. Phys Rev Lett 2017; 119:227001. [PMID: 29286823 DOI: 10.1103/physrevlett.119.227001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Indexed: 06/07/2023]
Abstract
We explore a new mechanism for switching magnetism and superconductivity in a magnetically frustrated iron-based superconductor using spin-polarized scanning tunneling microscopy (SPSTM). Our SPSTM study on single-crystal Sr_{2}VO_{3}FeAs shows that a spin-polarized tunneling current can switch the Fe-layer magnetism into a nontrivial C_{4} (2×2) order, which cannot be achieved by thermal excitation with an unpolarized current. Our tunneling spectroscopy study shows that the induced C_{4} (2×2) order has characteristics of plaquette antiferromagnetic order in the Fe layer and strongly suppresses superconductivity. Also, thermal agitation beyond the bulk Fe spin ordering temperature erases the C_{4} state. These results suggest a new possibility of switching local superconductivity by changing the symmetry of magnetic order with spin-polarized and unpolarized tunneling currents in iron-based superconductors.
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Affiliation(s)
- Seokhwan Choi
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Hyoung Joon Choi
- Department of Physics and Center for Computational Studies of Advanced Electronic Material Properties, Yonsei University, Seoul 03722, Korea
| | - Jong Mok Ok
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang 37673, Korea
| | - Yeonghoon Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Won-Jun Jang
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
- Center for Axion and Precision Physics Research, Institute for Basic Science (IBS), Daejeon 34051, Korea
| | - Alex Taekyung Lee
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - Young Kuk
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - SungBin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Korea
- Physics Department, Ewha Womans University, Seoul 03760, Korea
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Yunkyu Bang
- Department of Physics, Chonnam National University, Gwangju 61186, Korea
| | - Steven Johnston
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200, USA
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang 37673, Korea
| | - Jhinhwan Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
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48
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Cho D, Gye G, Lee J, Lee SH, Wang L, Cheong SW, Yeom HW. Correlated electronic states at domain walls of a Mott-charge-density-wave insulator 1T-TaS 2. Nat Commun 2017; 8:392. [PMID: 28855505 PMCID: PMC5577034 DOI: 10.1038/s41467-017-00438-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 06/29/2017] [Indexed: 11/09/2022] Open
Abstract
Domain walls in interacting electronic systems can have distinct localized states, which often govern physical properties and may lead to unprecedented functionalities and novel devices. However, electronic states within domain walls themselves have not been clearly identified and understood for strongly correlated electron systems. Here, we resolve the electronic states localized on domain walls in a Mott-charge-density-wave insulator 1T-TaS2 using scanning tunneling spectroscopy. We establish that the domain wall state decomposes into two nonconducting states located at the center of domain walls and edges of domains. Theoretical calculations reveal their atomistic origin as the local reconstruction of domain walls under the strong influence of electron correlation. Our results introduce a concept for the domain wall electronic property, the walls own internal degrees of freedom, which is potentially related to the controllability of domain wall electronic properties.The electronic states within domain walls in an interacting electronic system remain elusive. Here, Cho et al. report that the domain wall state in a charge-density-wave insulator 1T-TaS2 decomposes into two localized but nonconducting states at the center or edges of domain walls.
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Affiliation(s)
- Doohee Cho
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang, 790-784, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea
| | - Gyeongcheol Gye
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea
| | - Jinwon Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang, 790-784, Korea.,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea
| | - Sung-Hoon Lee
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang, 790-784, Korea
| | - Lihai Wang
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea.,Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Sang-Wook Cheong
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea.,Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Han Woong Yeom
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang, 790-784, Korea. .,Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea.
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49
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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. Sci Adv 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Han MG, Garlow JA, Marshall MSJ, Tiano AL, Wong SS, Cheong SW, Walker FJ, Ahn CH, Zhu Y. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes. Ultramicroscopy 2017; 176:80-85. [PMID: 28359670 DOI: 10.1016/j.ultramic.2017.03.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/03/2017] [Accepted: 01/22/2017] [Indexed: 11/19/2022]
Abstract
The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.
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Affiliation(s)
- Myung-Geun Han
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Joseph A Garlow
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794, USA
| | | | - Amanda L Tiano
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Stanislaus S Wong
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA; Department of Chemistry, Stony Brook University, Stony Brook, NY 11974, USA
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854, USA
| | - Frederick J Walker
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Charles H Ahn
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973, USA
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