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Roos M, Muhl IF, Schmidt M, Morais CV, Zimmer FM. Effects of third-neighbor interactions on the frustrated quantum Ising model. Phys Rev E 2024; 109:014144. [PMID: 38366410 DOI: 10.1103/physreve.109.014144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/22/2023] [Indexed: 02/18/2024]
Abstract
We investigate thermal and quantum phase transitions of the J_{1}-J_{2}-J_{3} transverse Ising model on the square lattice. The model is studied within a cluster mean-field decoupling, which allows us to describe phase diagrams and the free-energy landscape in the neighborhood of phase transitions. Our findings indicate that the third-neighbor coupling (J_{3}) can affect the nature of phase transitions of the model. In particular, ferromagnetic third-neighbor couplings favor the onset of continuous order-disorder phase transitions, eliminating the tricritical point of the superantiferromagnetic-paramagnetic (SAFM-PM) phase boundary. On the other hand, the enhancement of frustration introduced by weak antiferromagnetic J_{3} gives rise to the staggered dimer phase favoring the onset of discontinuous classical phase transitions. Moreover, we find that quantum annealed criticality (QAC), which takes place when the classical discontinuous phase transition becomes critical by the enhancement of quantum fluctuations introduced by the transverse magnetic field, is eliminated from the SAFM-PM phase boundary by a relatively weak ferromagnetic J_{3}. Nevertheless, this change in the nature of phase transitions can still be observed in the presence of antiferromagnetic third-neighbor couplings being also found in the staggered-dimer phase boundary. Therefore, our findings support that QAC persists under the presence of frustrated antiferromagnetic third-neighbor couplings and is suppressed when these couplings are ferromagnetic, suggesting that frustration plays a central role in the onset of QAC.
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Affiliation(s)
- M Roos
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, Rio Grande do Sul, Brazil
| | - I F Muhl
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, Rio Grande do Sul, Brazil
| | - M Schmidt
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, Rio Grande do Sul, Brazil
| | - C V Morais
- Instituto de Física e Matemática - Universidade Federal de Pelotas, 96010-900 Pelotas, Rio Grande do Sul, Brazil
| | - F M Zimmer
- Instituto de Física, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, Mato Grosso do Sul, Brazil
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2
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Xiang J, Zhang C, Gao Y, Schmidt W, Schmalzl K, Wang CW, Li B, Xi N, Liu XY, Jin H, Li G, Shen J, Chen Z, Qi Y, Wan Y, Jin W, Li W, Sun P, Su G. Giant magnetocaloric effect in spin supersolid candidate Na 2BaCo(PO 4) 2. Nature 2024; 625:270-275. [PMID: 38200301 DOI: 10.1038/s41586-023-06885-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/21/2023] [Indexed: 01/12/2024]
Abstract
Supersolid, an exotic quantum state of matter that consists of particles forming an incompressible solid structure while simultaneously showing superfluidity of zero viscosity1, is one of the long-standing pursuits in fundamental research2,3. Although the initial report of 4He supersolid turned out to be an artefact4, this intriguing quantum matter has inspired enthusiastic investigations into ultracold quantum gases5-8. Nevertheless, the realization of supersolidity in condensed matter remains elusive. Here we find evidence for a quantum magnetic analogue of supersolid-the spin supersolid-in the recently synthesized triangular-lattice antiferromagnet Na2BaCo(PO4)2 (ref. 9). Notably, a giant magnetocaloric effect related to the spin supersolidity is observed in the demagnetization cooling process, manifesting itself as two prominent valley-like regimes, with the lowest temperature attaining below 100 mK. Not only is there an experimentally determined series of critical fields but the demagnetization cooling profile also shows excellent agreement with the theoretical simulations with an easy-axis Heisenberg model. Neutron diffractions also successfully locate the proposed spin supersolid phases by revealing the coexistence of three-sublattice spin solid order and interlayer incommensurability indicative of the spin superfluidity. Thus, our results reveal a strong entropic effect of the spin supersolid phase in a frustrated quantum magnet and open up a viable and promising avenue for applications in sub-kelvin refrigeration, especially in the context of persistent concerns about helium shortages10,11.
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Affiliation(s)
- Junsen Xiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Chuandi Zhang
- School of Physics, Beihang University, Beijing, China
| | - Yuan Gao
- School of Physics, Beihang University, Beijing, China
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Wolfgang Schmidt
- Jülich Centre for Neutron Science at Institut Laue-Langevin (ILL), Forschungszentrum Jülich GmbH, Grenoble Cedex 9, France
| | - Karin Schmalzl
- Jülich Centre for Neutron Science at Institut Laue-Langevin (ILL), Forschungszentrum Jülich GmbH, Grenoble Cedex 9, France
| | - Chin-Wei Wang
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales, Australia
| | - Bo Li
- School of Physics, Beihang University, Beijing, China
| | - Ning Xi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Xin-Yang Liu
- School of Physics, Beihang University, Beijing, China
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Hai Jin
- Department of Astronomy, Tsinghua University, Beijing, China
| | - Gang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jun Shen
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Ziyu Chen
- School of Physics, Beihang University, Beijing, China
| | - Yang Qi
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China
| | - Yuan Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Wentao Jin
- School of Physics, Beihang University, Beijing, China.
| | - Wei Li
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China.
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijng, China.
- Peng Huanwu Collaborative Center for Research and Education, Beihang University, Beijing, China.
| | - Peijie Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
| | - Gang Su
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijng, China.
- Kavli Institute for Theoretical Sciences, and School of Physical Sciences, University of Chinese Academy of Sciences, Beijng, China.
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3
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Chi R, Liu Y, Wan Y, Liao HJ, Xiang T. Spin Excitation Spectra of Anisotropic Spin-1/2 Triangular Lattice Heisenberg Antiferromagnets. PHYSICAL REVIEW LETTERS 2022; 129:227201. [PMID: 36493423 DOI: 10.1103/physrevlett.129.227201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 09/12/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
Investigation of dynamical excitations is difficult but crucial to the understanding of many exotic quantum phenomena discovered in quantum materials. This is particularly true for highly frustrated quantum antiferromagnets whose dynamical properties deviate strongly from theoretical predictions made based on the spin-wave or other approximations. Here, we present a large-scale numerical calculation on the dynamical correlation functions of spin-1/2 triangular Heisenberg model using a state-of-the-art tensor network renormalization group method. The calculated results allow us to gain for the first time a comprehensive picture on the nature of spin excitation spectra in this highly frustrated quantum system. It provides a quantitative account for all the key features of the dynamical spectra disclosed by inelastic neutron scattering measurements for Ba_{3}CoSb_{2}O_{9}, revealing the importance of the interplay between low- and high-energy excitations and its renormalization effect to the low-energy magnon bands and high-energy continuums. We identify the longitudinal Higgs modes in the intermediate-energy scale and predict the energy and momentum dependence of spectral functions along the three principal axes that can be verified by polarized neutron scattering experiments. Furthermore, we find that the spin excitation spectra weakly depend on the anisotropic ratio of the antiferromagnetic interaction.
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Affiliation(s)
- Runze Chi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Wan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Hai-Jun Liao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - T Xiang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100190, China
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4
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Kim J, Kim K, Choi E, Joon Ko Y, Woo Lee D, Ho Lim S, Hoon Jung J, Lee S. Magnetic phase diagram of a 2-dimensional triangular lattice antiferromagnet Na 2BaMn(PO 4) 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:475803. [PMID: 36174545 DOI: 10.1088/1361-648x/ac965f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
We report the magnetic phase transitions of a spin-5/2, 2-dimensional triangular lattice antiferromagnet (AFM) Na2BaMn(PO4)2. From specific heat measurements, we observe two magnetic transitions at temperatures 1.15 and 1.30 K at zero magnetic field. Detailed AC magnetic susceptibility measurements reveal multiple phases including the↑↑↓(up-up-down)-phase between 1.9 and 2.9 T at 47 mK when magnetic field is applied along thecaxis, implying that Na2BaMn(PO4)2is a classical 2dTL Heisenberg AFM with easy-axis anisotropy. However, it deviates from an ideal model as evidenced by a hump region with hysteresis between the↑↑↓andV-phases and weak phase transitions. Our work provides another experimental example to study frustrated magnetism in 2dTL AFM which also serves as a reference to understand the possible quantum spin liquid behavior and anomalous phase diagrams observed in sibling systems Na2BaM(PO4)2(M= Co, Ni).
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Affiliation(s)
- Jaewook Kim
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Kyoo Kim
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Eunsang Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310-3706, United States of America
| | - Young Joon Ko
- Department of Physics, Inha University, Incheon 22212, Republic of Korea
| | - Dong Woo Lee
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Sang Ho Lim
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
| | - Jong Hoon Jung
- Department of Physics, Inha University, Incheon 22212, Republic of Korea
| | - Seungsu Lee
- Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea
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5
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Huang Q, Rawl R, Xie WW, Chou ES, Zapf VS, Ding XX, Mauws C, Wiebe CR, Feng EX, Cao HB, Tian W, Ma J, Qiu Y, Butch N, Zhou HD. Non-magnetic ion site disorder effects on the quantum magnetism of a spin-1/2 equilateral triangular lattice antiferromagnet. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:205401. [PMID: 35189602 DOI: 10.1088/1361-648x/ac5703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
With the motivation to study how non-magnetic ion site disorder affects the quantum magnetism of Ba3CoSb2O9, a spin-1/2 equilateral triangular lattice antiferromagnet, we performed DC and AC susceptibility, specific heat, elastic and inelastic neutron scattering measurements on single crystalline samples of Ba2.87Sr0.13CoSb2O9with Sr doping on non-magnetic Ba2+ion sites. The results show that Ba2.87Sr0.13CoSb2O9exhibits (i) a two-step magnetic transition at 2.7 K and 3.3 K, respectively; (ii) a possible canted 120 degree spin structure at zero field with reduced ordered moment as 1.24μB/Co; (iii) a series of spin state transitions for bothH∥ab-plane andH∥c-axis. ForH∥ab-plane, the magnetization plateau feature related to the up-up-down phase is significantly suppressed; (iv) an inelastic neutron scattering spectrum with only one gapped mode at zero field, which splits to one gapless and one gapped mode at 9 T. All these features are distinctly different from those observed for the parent compound Ba3CoSb2O9, which demonstrates that the non-magnetic ion site disorder (the Sr doping) plays a complex role on the magnetic properties beyond the conventionally expected randomization of the exchange interactions. We propose the additional effects including the enhancement of quantum spin fluctuations and introduction of a possible spatial anisotropy through the local structural distortions.
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Affiliation(s)
- Q Huang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States of America
| | - R Rawl
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States of America
| | - W W Xie
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, United States of America
| | - E S Chou
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States of America
| | - V S Zapf
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - X X Ding
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - C Mauws
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - C R Wiebe
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
- Department of Chemistry, University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - E X Feng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - H B Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - W Tian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - J Ma
- Laboratory of Artificial Structures and Quantum Control, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, People's Republic of China
| | - Y Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States of America
| | - N Butch
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States of America
| | - H D Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States of America
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States of America
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6
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Rao X, Hussain G, Huang Q, Chu WJ, Li N, Zhao X, Dun Z, Choi ES, Asaba T, Chen L, Li L, Yue XY, Wang NN, Cheng JG, Gao YH, Shen Y, Zhao J, Chen G, Zhou HD, Sun XF. Survival of itinerant excitations and quantum spin state transitions in YbMgGaO 4 with chemical disorder. Nat Commun 2021; 12:4949. [PMID: 34400621 PMCID: PMC8367942 DOI: 10.1038/s41467-021-25247-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
A recent focus of quantum spin liquid (QSL) studies is how disorder/randomness in a QSL candidate affects its true magnetic ground state. The ultimate question is whether the QSL survives disorder or the disorder leads to a “spin-liquid-like” state, such as the proposed random-singlet (RS) state. Since disorder is a standard feature of most QSL candidates, this question represents a major challenge for QSL candidates. YbMgGaO4, a triangular lattice antiferromagnet with effective spin-1/2 Yb3+ions, is an ideal system to address this question, since it shows no long-range magnetic ordering with Mg/Ga site disorder. Despite the intensive study, it remains unresolved as to whether YbMgGaO4 is a QSL or in the RS state. Here, through ultralow-temperature thermal conductivity and magnetic torque measurements, plus specific heat and DC magnetization data, we observed a residual κ0/T term and series of quantum spin state transitions in the zero temperature limit for YbMgGaO4. These observations strongly suggest that a QSL state with itinerant excitations and quantum spin fluctuations survives disorder in YbMgGaO4. It remains an open question as to whether the quantum spin liquid state survives material disorder, or is replaced by some spin-liquid like state. Here, Rao et al succeed in resolving a resolving a κ0/T residual in the thermal conductivity of YbMgGaO4 strongly suggesting the survival of the quantum spin liquid state.
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Affiliation(s)
- X Rao
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - G Hussain
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Q Huang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
| | - W J Chu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - N Li
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - X Zhao
- School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Z Dun
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
| | - E S Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA
| | - T Asaba
- Department of Physics, University of Michigan, Ann Arbor, MI, USA
| | - L Chen
- Department of Physics, University of Michigan, Ann Arbor, MI, USA
| | - L Li
- Department of Physics, University of Michigan, Ann Arbor, MI, USA
| | - X Y Yue
- Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, People's Republic of China
| | - N N Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - J-G Cheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Y H Gao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, People's Republic of China
| | - Y Shen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, People's Republic of China
| | - J Zhao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, People's Republic of China
| | - G Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, People's Republic of China. .,Department of Physics and HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong, The University of Hong Kong, Hong Kong, China.
| | - H D Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA.
| | - X F Sun
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui, People's Republic of China. .,Institute of Physical Science and Information Technology, Anhui University, Hefei, Anhui, People's Republic of China.
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7
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Yamamoto D, Sakurai T, Okuto R, Okubo S, Ohta H, Tanaka H, Uwatoko Y. Continuous control of classical-quantum crossover by external high pressure in the coupled chain compound CsCuCl 3. Nat Commun 2021; 12:4263. [PMID: 34253735 PMCID: PMC8275658 DOI: 10.1038/s41467-021-24542-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/23/2021] [Indexed: 11/16/2022] Open
Abstract
In solid materials, the parameters relevant to quantum effects, such as the spin quantum number, are basically determined and fixed at the chemical synthesis, which makes it challenging to control the amount of quantum correlations. We propose and demonstrate a method for active control of the classical-quantum crossover in magnetic insulators by applying external pressure. As a concrete example, we perform high-field, high-pressure measurements on CsCuCl3, which has the structure of weakly-coupled spin chains. The magnetization process experiences a continuous evolution from the semi-classical realm to the highly-quantum regime with increasing pressure. Based on the idea of "squashing” the spin chains onto a plane, we characterize the change in the quantum correlations by the change in the value of the local spin quantum number of an effective two-dimensional model. This opens a way to access the tunable classical-quantum crossover of two-dimensional spin systems by using alternative systems of coupled-chain compounds. In real materials, a spin quantum number assumes a fixed value, which makes it challenging to realize a crossover between quantum and classical spin regimes. Here the authors demonstrate such a crossover in a weakly coupled chain compound by controlling the amount of quantum correlations, in the form of the inverse spin quantum number, with external pressure.
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Affiliation(s)
- Daisuke Yamamoto
- Department of Physics, Nihon University, Tokyo, Japan. .,Department of Physics and Mathematics, Aoyama Gakuin University, Kanagawa, Japan.
| | - Takahiro Sakurai
- Research Facility Center for Science and Technology, Kobe University, Kobe, Japan.
| | - Ryosuke Okuto
- Graduate School of Science, Kobe University, Kobe, Japan
| | - Susumu Okubo
- Molecular Photoscience Research Center, Kobe University, Kobe, Japan
| | - Hitoshi Ohta
- Molecular Photoscience Research Center, Kobe University, Kobe, Japan
| | - Hidekazu Tanaka
- Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| | - Yoshiya Uwatoko
- Institute for Solid State Physics, The University of Tokyo, Chiba, Japan
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8
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Frantz GLK, Schmidt M, Zimmer FM. Thermally driven state in a spin-1 model with competing interactions. Phys Rev E 2021; 103:032125. [PMID: 33862719 DOI: 10.1103/physreve.103.032125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
We study a recently proposed spin-1 model with competing antiferromagnetic first-neighbor interaction and a third-neighbor coupling mediated by nonmagnetic states, which reproduces topological features of the phase diagrams of high-T_{c} superconductors [S. A. Cannas and D. A. Stariolo, Phys. Rev. E 99, 042137 (2019)2470-004510.1103/PhysRevE.99.042137]. We employ a cluster mean-field approach to investigate effects of crystal field anisotropy on the phase transitions hosted by this model. At low temperatures, the temperature-crystal field phase diagram exhibits superantiferromagnetic (SAF), antiferromagnetic (AF), and paramagnetic (PM) phases. In addition, we found a thermally driven state between SAF and PM phases. This thermally driven state and the SAF phase appears in the phase diagram as a domelike structure. Our calculations indicate that only second-order phase transitions occur in the PM-AF phase boundary, as suggested by previous Monte Carlo simulations.
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Affiliation(s)
- G L K Frantz
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - M Schmidt
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - F M Zimmer
- Instituto de Física, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, MS, Brazil
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9
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Schmidt M, Kellermann N, Zimmer FM. Transverse field effects on the competition between antiferromagnetic and cluster spin-glass phases. Phys Rev E 2020; 102:032139. [PMID: 33075931 DOI: 10.1103/physreve.102.032139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/07/2020] [Indexed: 11/07/2022]
Abstract
We investigate a disordered cluster Ising antiferromagnet in the presence of a transverse field. By adopting a replica cluster mean-field framework, we analyze the role of quantum fluctuations in a model with competing short-range antiferromagnetic and intercluster disordered interactions. The model exhibits paramagnetic (PM), antiferromagnetic (AF), and cluster spin-glass (CSG) phases, which are separated by thermal and quantum phase transitions. A scenario of strong competition between AF and CSG unveils a number of interesting phenomena induced by quantum fluctuations, including a quantum PM state and quantum driven criticality. The latter occurs when the thermally driven PM-AF discontinuous phase transition becomes continuous at strong transverse fields. Analogous phenomena have been reported in a number of systems, but a description of underlying mechanisms is still required. Our results indicate that quantum driven criticality can be found in a highly competitive regime of disordered antiferromagnets, which is in consonance with recent findings in spin models with competing interactions.
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Affiliation(s)
- M Schmidt
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - N Kellermann
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - F M Zimmer
- Instituto de Física, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, MS, Brazil
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10
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Li M, Plumer ML, Quirion G. Effects of interlayer and bi-quadratic exchange coupling on layered triangular lattice antiferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:135803. [PMID: 31801115 DOI: 10.1088/1361-648x/ab5ea6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The magnetic field evolution of ground spin states of the stacked planar triangular antiferromagnet with antiferromagnetic interlayer interaction J c is explored using a minimal 3D classical Heisenberg model. A bi-quadratic coupling is also used to mimic the effect of spin fluctuations (Zhitomirsky 2015 J. Phys.: Conf. Ser. 592 012110) which are known to stabilize the magnetization plateau. A single ion anisotropy is included and states with a magnetic field applied in the ab plane and along the c axis are determined. For [Formula: see text]-plane, an additional new state, in contrast to 2D model (Zhitomirsky 2015 J. Phys.: Conf. Ser. 592 012110), is obtained with weak interlayer interaction, while the magnetization plateau vanishes at large J c and other new states with z components of spins emerge. For [Formula: see text]-axis, an extra state, compared with 2D model, is obtained with a weak interlayer interaction. When J c is large enough, only the state corresponding to the Umbrella phase in 2D model exits.
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Affiliation(s)
- M Li
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Newfoundland A1B 3X7, Canada
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11
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Ferreira T, Xing J, Sanjeewa LD, Sefat AS. Frustrated Magnetism in Triangular Lattice TlYbS 2 Crystals Grown via Molten Flux. Front Chem 2020; 8:127. [PMID: 32175311 PMCID: PMC7054481 DOI: 10.3389/fchem.2020.00127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/12/2020] [Indexed: 11/23/2022] Open
Abstract
The triangular lattice compound TlYbS2 was prepared as large single crystals via a molten flux growth technique using sodium chloride. Anisotropic magnetic susceptibility measurements down to 0.4 K indicate a complete absence of long-range magnetic order. Despite this lack of long-range order, short-range antiferromagnetic interactions are evidenced through broad transitions, suggesting frustrated behavior. Variable magnetic field measurements reveal metamagnetic behavior at temperatures ≤2 K. Complex low temperature field-tunable magnetic behavior, in addition to no observable long-range order down to 0.4 K, suggest that TlYbS2 is a frustrated magnet and a possible quantum spin liquid candidate.
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Affiliation(s)
- Timothy Ferreira
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, United States
| | - Jie Xing
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, United States
| | - Liurukara D Sanjeewa
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, United States
| | - Athena S Sefat
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN, United States
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12
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Kellermann N, Schmidt M, Zimmer FM. Quantum Ising model on the frustrated square lattice. Phys Rev E 2019; 99:012134. [PMID: 30780286 DOI: 10.1103/physreve.99.012134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Indexed: 06/09/2023]
Abstract
We investigate the role of a transverse field on the Ising square antiferromagnet with first (J_{1}) and second (J_{2}) neighbor interactions. Using a cluster mean-field approach, we provide a telltale characterization of the frustration effects on the phase boundaries and entropy accumulation process emerging from the interplay between quantum and thermal fluctuations. We found that the paramagnetic (PM) and antiferromagnetic phases are separated by continuous phase transitions. On the other hand, continuous and discontinuous phase transitions, as well as tricriticality, are observed in the phase boundaries between PM and superantiferromagnetic phases. A rich scenario arises when a discontinuous phase transition occurs in the classical limit while quantum fluctuations recover criticality. We also find that the entropy accumulation process predicted to occur at temperatures close to the quantum critical point can be enhanced by frustration. Our results provide a description for the phase boundaries and entropy behavior that can help to identify the ratio J_{2}/J_{1} in possible experimental realizations of the quantum J_{1}-J_{2} Ising antiferromagnet.
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Affiliation(s)
- N Kellermann
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - M Schmidt
- Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - F M Zimmer
- Instituto de Física, Universidade Federal de Mato Grosso do Sul, 79070-900 Campo Grande, MS, Brazil
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13
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Benton O, Jaubert LDC, Singh RRP, Oitmaa J, Shannon N. Quantum Spin Ice with Frustrated Transverse Exchange: From a π-Flux Phase to a Nematic Quantum Spin Liquid. PHYSICAL REVIEW LETTERS 2018; 121:067201. [PMID: 30141668 DOI: 10.1103/physrevlett.121.067201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Quantum spin ice materials, pyrochlore magnets with competing Ising and transverse exchange interactions, have been widely discussed as candidates for a quantum spin-liquid ground state. Here, motivated by quantum chemical calculations for Pr pyrochlores, we present the results of a study for frustrated transverse exchange. Using a combination of variational calculations, exact diagonalization, numerical linked-cluster and series expansions, we find that the previously studied U(1) quantum spin liquid, in its π-flux phase, transforms into a nematic quantum spin liquid at a high-symmetry, SU(2) point.
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Affiliation(s)
- Owen Benton
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - L D C Jaubert
- CNRS, Université de Bordeaux, LOMA, UMR 5798, 33400 Talence, France
| | - Rajiv R P Singh
- Department of Physics, University of California, Davis, California 95616, USA
| | - Jaan Oitmaa
- School of Physics, The University of New South Wales, Sydney 2052, Australia
| | - Nic Shannon
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
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14
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Kamiya Y, Ge L, Hong T, Qiu Y, Quintero-Castro DL, Lu Z, Cao HB, Matsuda M, Choi ES, Batista CD, Mourigal M, Zhou HD, Ma J. The nature of spin excitations in the one-third magnetization plateau phase of Ba 3CoSb 2O 9. Nat Commun 2018; 9:2666. [PMID: 29991805 PMCID: PMC6039502 DOI: 10.1038/s41467-018-04914-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 05/21/2018] [Indexed: 11/25/2022] Open
Abstract
Magnetization plateaus in quantum magnets—where bosonic quasiparticles crystallize into emergent spin superlattices—are spectacular yet simple examples of collective quantum phenomena escaping classical description. While magnetization plateaus have been observed in a number of spin-1/2 antiferromagnets, the description of their magnetic excitations remains an open theoretical and experimental challenge. Here, we investigate the dynamical properties of the triangular-lattice spin-1/2 antiferromagnet Ba3CoSb2O9 in its one-third magnetization plateau phase using a combination of nonlinear spin-wave theory and neutron scattering measurements. The agreement between our theoretical treatment and the experimental data demonstrates that magnons behave semiclassically in the plateau in spite of the purely quantum origin of the underlying magnetic structure. This allows for a quantitative determination of Ba3CoSb2O9 exchange parameters. We discuss the implication of our results to the deviations from semiclassical behavior observed in zero-field spin dynamics of the same material and conclude they must have an intrinsic origin. Frustrated magnetic materials attract significant interest because their properties can become dominated by quantum fluctuations. Here the authors show that excitations in the plateau phase of a quantum magnet can be understood semiclassically even though the ground state involves strong quantum effects.
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Affiliation(s)
- Y Kamiya
- Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama, 351-0198, Japan.
| | - L Ge
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Tao Hong
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Y Qiu
- NIST Centre for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - D L Quintero-Castro
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109, Berlin, Germany
| | - Z Lu
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109, Berlin, Germany
| | - H B Cao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - M Matsuda
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - E S Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - C D Batista
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.,Neutron Scattering Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - M Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - H D Zhou
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA.,Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - J Ma
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA. .,Key Laboratory of Artificial Structures and Quantum Control, Department of Physics and Astronomy, Shanghai Jiao Tong University, 200240, Shanghai, China. .,Collaborative Innovation Center of Advanced Microstructures, 210093, Nanjing, Jiangsu, China.
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15
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Ito S, Kurita N, Tanaka H, Ohira-Kawamura S, Nakajima K, Itoh S, Kuwahara K, Kakurai K. Structure of the magnetic excitations in the spin-1/2 triangular-lattice Heisenberg antiferromagnet Ba 3CoSb 2O 9. Nat Commun 2017; 8:235. [PMID: 28794443 PMCID: PMC5550445 DOI: 10.1038/s41467-017-00316-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/16/2017] [Indexed: 11/09/2022] Open
Abstract
A spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) is a prototypical frustrated quantum magnet, which exhibits remarkable quantum many-body effects that arise from the synergy between spin frustration and quantum fluctuation. The ground-state properties of a spin-1/2 TLHAF are theoretically well understood. However, the theoretical consensus regarding the magnetic excitations is limited. The experimental study of the magnetic excitations in spin-1/2 TLHAFs has also been limited. Here we show the structure of magnetic excitations in the spin-1/2 TLHAF Ba3CoSb2O9 investigated by inelastic neutron scattering. Significantly different from theoretical expectations, the excitation spectrum has a three-stage energy structure. The lowest-energy first stage is composed of dispersion branches of single-magnon excitations. The second and third stages are dispersive continua accompanied by a columnar continuum extending above 10 meV, which is six times larger than the exchange interaction J = 1.67 meV. Our results indicate the shortcomings of the current theoretical framework. Two-dimensional frustrated magnets are heavily studied because theories predict that quantum effects may lead to the emergence of fractionalized excitations. Ito et al. use inelastic neutron scattering to show that the excitation spectrum of Ba3CoSb2O9 disagrees with current theoretical expectations.
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Affiliation(s)
- Saya Ito
- Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Nobuyuki Kurita
- Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Hidekazu Tanaka
- Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
| | - Seiko Ohira-Kawamura
- Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki, 319-1195, Japan
| | - Kenji Nakajima
- Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki, 319-1195, Japan
| | - Shinichi Itoh
- Neutron Science Division, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan
| | - Keitaro Kuwahara
- Institute of Quantum Beam Science, Ibaraki University, Mito, 310-8512, Japan
| | - Kazuhisa Kakurai
- Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan
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16
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Ma J, Kamiya Y, Hong T, Cao HB, Ehlers G, Tian W, Batista CD, Dun ZL, Zhou HD, Matsuda M. Static and Dynamical Properties of the Spin-1/2 Equilateral Triangular-Lattice Antiferromagnet Ba_{3}CoSb_{2}O_{9}. PHYSICAL REVIEW LETTERS 2016; 116:087201. [PMID: 26967439 DOI: 10.1103/physrevlett.116.087201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Indexed: 06/05/2023]
Abstract
We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular-lattice antiferromagnet Ba_{3}CoSb_{2}O_{9}. Besides confirming that the Co^{2+} magnetic moments lie in the ab plane for zero magnetic field and then determining all the exchange parameters of the minimal quasi-2D spin Hamiltonian, we provide conclusive experimental evidence of magnon decay through observation of intrinsic line broadening. Through detailed comparisons with the linear and nonlinear spin-wave theories, we also point out that the large-S approximation, which is conventionally employed to predict magnon decay in noncollinear magnets, is inadequate to explain our experimental observation. Thus, our results call for a new theoretical framework for describing excitation spectra in low-dimensional frustrated magnets under strong quantum effects.
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Affiliation(s)
- J Ma
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Y Kamiya
- iTHES Research Group and Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Tao Hong
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - H B Cao
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - G Ehlers
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W Tian
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - C D Batista
- Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Z L Dun
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - H D Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310-3706, USA
| | - M Matsuda
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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