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Zhang Q, He WY, Zhang Y, Chen Y, Jia L, Hou Y, Ji H, Yang H, Zhang T, Liu L, Gao HJ, Jung TA, Wang Y. Quantum spin liquid signatures in monolayer 1T-NbSe 2. Nat Commun 2024; 15:2336. [PMID: 38485980 PMCID: PMC10940636 DOI: 10.1038/s41467-024-46612-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/01/2024] [Indexed: 03/18/2024] Open
Abstract
Quantum spin liquids (QSLs) are in a quantum disordered state that is highly entangled and has fractional excitations. As a highly sought-after state of matter, QSLs were predicted to host spinon excitations and to arise in frustrated spin systems with large quantum fluctuations. Here we report on the experimental observation and theoretical modeling of QSL signatures in monolayer 1T-NbSe2, which is a newly emerging two-dimensional material that exhibits both charge-density-wave (CDW) and correlated insulating behaviors. By using scanning tunneling microscopy and spectroscopy (STM/STS), we confirm the presence of spin fluctuations in monolayer 1T-NbSe2 by observing the Kondo resonance as monolayer 1T-NbSe2 interacts with metallic monolayer 1H-NbSe2. Subsequent STM/STS imaging of monolayer 1T-NbSe2 at the Hubbard band energy further reveals a long-wavelength charge modulation, in agreement with the spinon modulation expected for QSLs. By depositing manganese-phthalocyanine (MnPc) molecules with spin S = 3/2 onto monolayer 1T-NbSe2, new STS resonance peaks emerge at the Hubbard band edges of monolayer 1T-NbSe2. This observation is consistent with the spinon Kondo effect induced by a S = 3/2 magnetic impurity embedded in a QSL. Taken together, these experimental observations indicate that monolayer 1T-NbSe2 is a new promising QSL material.
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Affiliation(s)
- Quanzhen Zhang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Wen-Yu He
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yu Zhang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China.
- Advanced Research Institute of Multidisciplinary Sciences, Beijing Institute of Technology, Beijing, 100081, China.
| | - Yaoyao Chen
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Liangguang Jia
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Yanhui Hou
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Hongyan Ji
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Huixia Yang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Teng Zhang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Liwei Liu
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China
| | - Hong-Jun Gao
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Thomas A Jung
- Laboratory for X-ray Nanoscience and Technologies, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - Yeliang Wang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing, 100081, China.
- Yangtze Delta Region Academy, Beijing Institute of Technology, Jiaxing, Zhejiang, 314000, China.
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2
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Park P, Cho W, Kim C, An Y, Kang YG, Avdeev M, Sibille R, Iida K, Kajimoto R, Lee KH, Ju W, Cho EJ, Noh HJ, Han MJ, Zhang SS, Batista CD, Park JG. Tetrahedral triple-Q magnetic ordering and large spontaneous Hall conductivity in the metallic triangular antiferromagnet Co 1/3TaS 2. Nat Commun 2023; 14:8346. [PMID: 38102124 PMCID: PMC10724158 DOI: 10.1038/s41467-023-43853-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
The triangular lattice antiferromagnet (TLAF) has been the standard paradigm of frustrated magnetism for several decades. The most common magnetic ordering in insulating TLAFs is the 120° structure. However, a new triple-Q chiral ordering can emerge in metallic TLAFs, representing the short wavelength limit of magnetic skyrmion crystals. We report the metallic TLAF Co1/3TaS2 as the first example of tetrahedral triple-Q magnetic ordering with the associated topological Hall effect (non-zero σxy(H = 0)). We also present a theoretical framework that describes the emergence of this magnetic ground state, which is further supported by the electronic structure measured by angle-resolved photoemission spectroscopy. Additionally, our measurements of the inelastic neutron scattering cross section are consistent with the calculated dynamical structure factor of the tetrahedral triple-Q state.
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Affiliation(s)
- Pyeongjae Park
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Woonghee Cho
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Chaebin Kim
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeochan An
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics & Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yoon-Gu Kang
- Department of Physics, KAIST, Daejeon, 34141, Republic of Korea
| | - Maxim Avdeev
- Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW, 2234, Australia
- School of Chemistry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Romain Sibille
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Kazuki Iida
- Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan
| | - Ryoichi Kajimoto
- Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Ki Hoon Lee
- Department of Physics, Incheon National University, Incheon, 22012, Republic of Korea
| | - Woori Ju
- Department of Physics, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - En-Jin Cho
- Department of Physics, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Han-Jin Noh
- Department of Physics, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Myung Joon Han
- Department of Physics, KAIST, Daejeon, 34141, Republic of Korea
| | - Shang-Shun Zhang
- School of Physics and Astronomy and William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Cristian D Batista
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
- Quantum Condensed Matter Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Je-Geun Park
- Center for Quantum Materials, Seoul National University, Seoul, 08826, Republic of Korea.
- Department of Physics & Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
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3
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Xie T, Eberharter AA, Xing J, Nishimoto S, Brando M, Khanenko P, Sichelschmidt J, Turrini AA, Mazzone DG, Naumov PG, Sanjeewa LD, Harrison N, Sefat AS, Normand B, Läuchli AM, Podlesnyak A, Nikitin SE. Complete field-induced spectral response of the spin-1/2 triangular-lattice antiferromagnet CsYbSe 2. NPJ QUANTUM MATERIALS 2023; 8:48. [PMID: 38666238 PMCID: PMC11041694 DOI: 10.1038/s41535-023-00580-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/11/2023] [Indexed: 04/28/2024]
Abstract
Fifty years after Anderson's resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe2, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling. We then measure the complex evolution of the excitation spectrum, finding extensive continuum features near the 120°-ordered state, throughout the 1/3-magnetization plateau and beyond this up to saturation. We perform cylinder matrix-product-state (MPS) calculations to obtain an unbiased numerical benchmark for the TLHAF and spectacular agreement with the experimental spectra. The measured and calculated longitudinal spectral functions reflect the role of multi-magnon bound and scattering states. These results provide valuable insight into unconventional field-induced spin excitations in frustrated quantum materials.
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Affiliation(s)
- Tao Xie
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - A. A. Eberharter
- Institut für Theoretische Physik, Universität Innsbruck, Innsbruck, Austria
| | - Jie Xing
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - S. Nishimoto
- Department of Physics, Technical University Dresden, 01069 Dresden, Germany
- Institute for Theoretical Solid State Physics, IFW Dresden, 01069 Dresden, Germany
| | - M. Brando
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - P. Khanenko
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - J. Sichelschmidt
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - A. A. Turrini
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - D. G. Mazzone
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - P. G. Naumov
- Quantum Criticality and Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Orange Quantum Systems B.V., Elektronicaweg 2, 2628 XG Delft, The Netherlands
| | - L. D. Sanjeewa
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - N. Harrison
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - Athena S. Sefat
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - B. Normand
- Laboratory for Theoretical and Computational Physics, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A. M. Läuchli
- Laboratory for Theoretical and Computational Physics, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - S. E. Nikitin
- Quantum Criticality and Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
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4
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Wakamatsu K, Suzuki Y, Fujii T, Miyagawa K, Taniguchi H, Kanoda K. Thermoelectric signature of quantum critical phase in a doped spin-liquid candidate. Nat Commun 2023; 14:3679. [PMID: 37344458 DOI: 10.1038/s41467-023-39217-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 05/31/2023] [Indexed: 06/23/2023] Open
Abstract
Quantum spin liquid is a nontrivial magnetic state of longstanding interest, in which spins are strongly correlated and entangled but do not order; further intriguing is its doped version, which possibly hosts strange metal and unconventional superconductivity. A promising candidate of the doped spin liquid is a triangular-lattice organic conductor, κ-(BEDT-TTF)4Hg2.89Br8, recently found to hold metallicity, spin-liquid-like magnetism, and BEC-like superconductivity. The nature of the metallic state with the spin-liquid behaviour is awaiting to be further clarified. Here, we report the thermoelectric signature that mobile holes in the spin liquid background are in a quantum critical state and it pertains to the BEC-like superconductivity. The Seebeck coefficient divided by temperature, S/T, is enhanced on cooling with logarithmic divergence indicative of quantum criticality. Furthermore, the logarithmic enhancement is correlated with the superconducting transition temperature under pressure variation, and the temperature and magnetic field profile of S/T upon the superconducting transition change with pressure in a consistent way with the previously suggested BEC-BCS crossover. The present results reveal that the quantum criticality in a doped spin liquid emerges in a phase, not at a point, and is involved in the unconventional BEC-like nature.
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Affiliation(s)
- K Wakamatsu
- Department of Applied Physics, University of Tokyo; Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Y Suzuki
- Department of Applied Physics, University of Tokyo; Bunkyo-ku, Tokyo, 113-8656, Japan
| | - T Fujii
- Cryogenic Research Center, University of Tokyo; Bunkyo-ku, Tokyo, 113-0032, Japan
| | - K Miyagawa
- Department of Applied Physics, University of Tokyo; Bunkyo-ku, Tokyo, 113-8656, Japan
| | - H Taniguchi
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - K Kanoda
- Department of Applied Physics, University of Tokyo; Bunkyo-ku, Tokyo, 113-8656, Japan.
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.
- Physics Institute, University of Stuttgart, Pfaffenwaldring 57, D-70569, Stuttgart, Germany.
- Department of Advanced Materials Science, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, 277-8561, Chiba, Japan.
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5
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Chen G, Rösner M, Lado JL. Controlling magnetic frustration in 1T-TaS 2via Coulomb engineered long-range interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:485805. [PMID: 36202090 DOI: 10.1088/1361-648x/ac9812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Magnetic frustrations in two-dimensional materials provide a rich playground to engineer unconventional phenomena. However, despite intense efforts, a realization of tunable frustrated magnetic order in two-dimensional materials remains an open challenge. Here we propose Coulomb engineering as a versatile strategy to tailor magnetic ground states in layered materials. Using the frustrated van der Waals monolayer 1T-TaS2as an example, we show how long-range Coulomb interactions renormalize the low energy nearly flat band structure, leading to a Heisenberg model which depends on the Coulomb interactions. Based on this, we show that superexchange couplings in the material can be precisely tailored by means of environmental dielectric screening, ultimately allowing to externally drive the material towards a tunable frustrated regime. Our results put forward Coulomb engineering as a powerful tool to manipulate magnetic properties of van der Waals materials.
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Affiliation(s)
- Guangze Chen
- Department of Applied Physics, Aalto University, 02150 Espoo, Finland
| | - Malte Rösner
- Institute for Molecules and Materials, Radboud University, NL-6525 AJ Nijmegen, The Netherlands
| | - Jose L Lado
- Department of Applied Physics, Aalto University, 02150 Espoo, Finland
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6
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Jin HK, Sun RY, Tu HH, Zhou Y. Unveiling a critical stripy state in the triangular-lattice SU(4) spin-orbital model. Sci Bull (Beijing) 2022; 67:918-923. [DOI: 10.1016/j.scib.2022.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/08/2022] [Accepted: 02/28/2022] [Indexed: 10/18/2022]
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7
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Zhang YH, Sheng DN, Vishwanath A. SU(4) Chiral Spin Liquid, Exciton Supersolid, and Electric Detection in Moiré Bilayers. PHYSICAL REVIEW LETTERS 2021; 127:247701. [PMID: 34951785 DOI: 10.1103/physrevlett.127.247701] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 09/09/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
We propose a moiré bilayer as a platform where exotic quantum phases can be stabilized and electrically detected. Moiré bilayers consist of two separate moiré superlattice layers coupled through the interlayer Coulomb repulsion. In the small distance limit, an SU(4) spin can be formed by combining layer pseudospin and the real spin. As a concrete example, we study an SU(4) spin model on triangular lattice in the fundamental representation. By tuning a three-site ring exchange term K∼(t^{3}/U^{2}), we find the SU(4) symmetric crystallized phase and an SU(4)_{1} chiral spin liquid at the balanced filling. We also predict two different exciton supersolid phases with interlayer coherence at imbalanced filling under displacement field. Especially, the system can simulate an SU(2) Bose-Einstein condensation by injecting interlayer excitons into the magnetically ordered Mott insulator at the layer polarized limit. Smoking gun evidences of these phases can be obtained by measuring the pseudospin transport in the counterflow channel.
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Affiliation(s)
- Ya-Hui Zhang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - D N Sheng
- Department of Physics and Astronomy, California State University, Northridge, California 91330, USA
| | - Ashvin Vishwanath
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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8
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Bordelon MM, Wang X, Pajerowski DM, Banerjee A, Sherwin M, Brown CM, Eldeeb MS, Petersen T, Hozoi L, Rӧßler UK, Mourigal M, Wilson SD. Magnetic properties and signatures of ordering in triangular lattice antiferromagnet KCeO 2. PHYSICAL REVIEW. B 2021; 104:10.1103/PhysRevB.104.094421. [PMID: 37780895 PMCID: PMC10540645 DOI: 10.1103/physrevb.104.094421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
The magnetic ground state and the crystalline electric field level scheme of the triangular lattice antiferromagnet KCeO 2 are investigated. Below T N = 300 mK, KCeO 2 develops signatures of magnetic order in specific heat measurements and low energy inelastic neutron scattering data. Trivalent Ce 3 + ions in the D 3 d local environment of this compound exhibit large splittings among the lowest three 4 f 1 Kramers doublets defining for the free ion the J = 5 / 2 sextet and a ground state doublet with dipole character, consistent with recent theoretical predictions in M. S. Eldeeb et al. Phys. Rev. Materials 4, 124001 (2020). An unexplained, additional local mode appears, and potential origins of this anomalous mode are discussed.
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Affiliation(s)
- Mitchell M. Bordelon
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Xiaoling Wang
- Department of Physics and Center for Terahertz Science and Technology, University of California, Santa Barbara, California 93106, USA
| | - Daniel M. Pajerowski
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Arnab Banerjee
- Department of Physics, Purdue University, West Lafayette, Indiana 47906, USA
| | - Mark Sherwin
- Department of Physics and Center for Terahertz Science and Technology, University of California, Santa Barbara, California 93106, USA
| | - Craig M. Brown
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - M. S. Eldeeb
- Institute for Theoretical Solid State Physics, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - T. Petersen
- Institute for Theoretical Solid State Physics, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - L. Hozoi
- Institute for Theoretical Solid State Physics, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - U. K. Rӧßler
- Institute for Theoretical Solid State Physics, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Martin Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Stephen D. Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
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9
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Cookmeyer T, Motruk J, Moore JE. Four-Spin Terms and the Origin of the Chiral Spin Liquid in Mott Insulators on the Triangular Lattice. PHYSICAL REVIEW LETTERS 2021; 127:087201. [PMID: 34477420 DOI: 10.1103/physrevlett.127.087201] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
At strong repulsion, the triangular-lattice Hubbard model is described by s=1/2 spins with nearest-neighbor antiferromagnetic Heisenberg interactions and exhibits conventional 120° order. Using the infinite density matrix renormalization group and exact diagonalization, we study the effect of the additional four-spin interactions naturally generated from the underlying Mott-insulator physics of electrons as the repulsion decreases. Although these interactions have historically been connected with a gapless ground state with emergent spinon Fermi surface, we find that, at physically relevant parameters, they stabilize a chiral spin liquid (CSL) of Kalmeyer-Laughlin (KL) type, clarifying observations in recent studies of the Hubbard model. We then present a self-consistent solution based on a mean-field rewriting of the interaction to obtain a Hamiltonian with similarities to the parent Hamiltonian of the KL state, providing a physical understanding for the origin of the CSL.
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Affiliation(s)
- Tessa Cookmeyer
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Johannes Motruk
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Theoretical Physics, University of Geneva, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland
| | - Joel E Moore
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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10
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Jiang YF, Jiang HC. Topological Superconductivity in the Doped Chiral Spin Liquid on the Triangular Lattice. PHYSICAL REVIEW LETTERS 2020; 125:157002. [PMID: 33095631 DOI: 10.1103/physrevlett.125.157002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/04/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
It has long been proposed that doping a chiral spin liquid (CSL) or fractional quantum Hall state can give rise to topological superconductivity. Despite intensive effort, definitive evidences still remain lacking. We address this problem by studying the t-J model supplemented by time-reversal symmetry breaking chiral interaction J_{χ} on the triangular lattice using density-matrix renormalization group with a finite concentration δ of doped holes. It has been established that the undoped, i.e., δ=0, system has a CSL ground state in the parameter region 0.32≤J_{χ}/J≤0.56. Upon light doping, we find that the ground state of the system is consistent with a Luther-Emery liquid with power-law superconducting and charge-density-wave correlations but short-range spin-spin correlations. In particular, the superconducting correlations, whose pairing symmetry is consistent with d±id wave, are dominant at all hole doping concentrations. Our results provide direct evidences that doping the CSL on the triangular lattice can naturally give rise to topological superconductivity.
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Affiliation(s)
- Yi-Fan Jiang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, California 94025, USA
| | - Hong-Chen Jiang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, California 94025, USA
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11
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Li Y, Gegenwart P, Tsirlin AA. Spin liquids in geometrically perfect triangular antiferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:224004. [PMID: 32015221 DOI: 10.1088/1361-648x/ab724e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The cradle of quantum spin liquids, triangular antiferromagnets show strong proclivity to magnetic order and require deliberate tuning to stabilize a spin-liquid state. In this brief review, we juxtapose recent theoretical developments that trace the parameter regime of the spin-liquid phase, with experimental results for Co-based and Yb-based triangular antiferromagnets. Unconventional spin dynamics arising from both ordered and disordered ground states are discussed, and the notion of a geometrically perfect triangular system is scrutinized to demonstrate non-trivial imperfections that may assist magnetic frustration in stabilizing dynamic spin states with peculiar excitations.
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Affiliation(s)
- Yuesheng Li
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany. Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, 430074 Wuhan, People's Republic of China
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