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Fogh E, Nayak M, Prokhnenko O, Bartkowiak M, Munakata K, Soh JR, Turrini AA, Zayed ME, Pomjakushina E, Kageyama H, Nojiri H, Kakurai K, Normand B, Mila F, Rønnow HM. Field-induced bound-state condensation and spin-nematic phase in SrCu 2(BO 3) 2 revealed by neutron scattering up to 25.9 T. Nat Commun 2024; 15:442. [PMID: 38200029 PMCID: PMC10781965 DOI: 10.1038/s41467-023-44115-z] [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: 07/21/2023] [Accepted: 11/30/2023] [Indexed: 01/12/2024] Open
Abstract
In quantum magnetic materials, ordered phases induced by an applied magnetic field can be described as the Bose-Einstein condensation (BEC) of magnon excitations. In the strongly frustrated system SrCu2(BO3)2, no clear magnon BEC could be observed, pointing to an alternative mechanism, but the high fields required to probe this physics have remained a barrier to detailed investigation. Here we exploit the first purpose-built high-field neutron scattering facility to measure the spin excitations of SrCu2(BO3)2 up to 25.9 T and use cylinder matrix-product-states (MPS) calculations to reproduce the experimental spectra with high accuracy. Multiple unconventional features point to a condensation of S = 2 bound states into a spin-nematic phase, including the gradients of the one-magnon branches and the persistence of a one-magnon spin gap. This gap reflects a direct analogy with superconductivity, suggesting that the spin-nematic phase in SrCu2(BO3)2 is best understood as a condensate of bosonic Cooper pairs.
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Affiliation(s)
- Ellen Fogh
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
| | - Mithilesh Nayak
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
| | | | - Maciej Bartkowiak
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109, Berlin, Germany
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, OX11 0QX, UK
| | - Koji Munakata
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan
| | - Jian-Rui Soh
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Alexandra A Turrini
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - Mohamed E Zayed
- Department of Physics, Carnegie Mellon University in Qatar, Education City, PO Box 24866, Doha, Qatar
| | - Ekaterina Pomjakushina
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Hiroshi Kageyama
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Kazuhisa Kakurai
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan
| | - Bruce Normand
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
- Laboratory for Theoretical and Computational Physics, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - Frédéric Mila
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Henrik M Rønnow
- Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
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Imajo S, Matsuyama N, Nomura T, Kihara T, Nakamura S, Marcenat C, Klein T, Seyfarth G, Zhong C, Kageyama H, Kindo K, Momoi T, Kohama Y. Magnetically Hidden State on the Ground Floor of the Magnetic Devil's Staircase. PHYSICAL REVIEW LETTERS 2022; 129:147201. [PMID: 36240417 DOI: 10.1103/physrevlett.129.147201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/20/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
We investigated the low-temperature and high-field thermodynamic and ultrasonic properties of SrCu_{2}(BO_{3})_{2}, which exhibits various plateaux in its magnetization curve above 27 T, called a magnetic Devil's staircase. The results of the present study confirm that magnetic crystallization, the first step of the staircase, occurs above 27 T as a first-order transition accompanied by a sharp singularity in heat capacity C_{p} and a kink in the elastic constant. In addition, we observe a thermodynamic anomaly at lower fields around 26 T, which has not been previously detected by any magnetic probes. At low temperatures, this magnetically hidden state has a large entropy and does not exhibit Schottky-type gapped behavior, which suggests the existence of low-energy collective excitations. Based on our observations and theoretical predictions, we propose that magnetic quadrupoles form a spin-nematic state around 26 T as a hidden state on the ground floor of the magnetic Devil's staircase.
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Affiliation(s)
- S Imajo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - N Matsuyama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T Nomura
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T Kihara
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - S Nakamura
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - C Marcenat
- Université Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, 38000 Grenoble, France
| | - T Klein
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, F-38000 Grenoble, France
| | - G Seyfarth
- LNCMI-EMFL, CNRS, Université Grenoble Alpes, INSA-T, UPS, F-38042 Grenoble, France
| | - C Zhong
- Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - H Kageyama
- Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan
| | - K Kindo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T Momoi
- Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Y Kohama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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Huang HX, Chen J, Ren W, Gao Y, Li W, Chen Y. Insulator-metal transition and quasi-flat-band of Shastry-Sutherland lattice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:345402. [PMID: 31096201 DOI: 10.1088/1361-648x/ab2228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Insulator-metal transition is investigated self-consistently on the frustrated Shastry-Sutherland lattice in the framework of Slave-Boson mean-field theory. Due to the presence of quasi-flat band structure characteristic, the system displays a spin-density-wave (SDW) insulating phase at the weak doping levels, which is robust against frustration, and it will be transited into an SDW metallic phase at high doping levels. As further increasing the doping, the temperature or the frustration on the diagonal linking bonds, the magnetic order m will be monotonically suppressed, resulting in the appearance of a paramagnetic metallic phase. Although the Fermi surface of the SDW metallic phase may be immersed by temperature, the number of mobile charges is robust against temperature at weak doping levels.
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Affiliation(s)
- Huai-Xiang Huang
- Department of Physics and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, People's Republic of China
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Trinh J, Mitra S, Panagopoulos C, Kong T, Canfield PC, Ramirez AP. Degeneracy of the 1/8 Plateau and Antiferromagnetic Phases in the Shastry-Sutherland Magnet TmB_{4}. PHYSICAL REVIEW LETTERS 2018; 121:167203. [PMID: 30387620 DOI: 10.1103/physrevlett.121.167203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Indexed: 06/08/2023]
Abstract
The 1/8 fractional plateau phase (1/8 FPP) in Shastry-Sutherland lattice (SSL) spin systems has been viewed an exemplar of emergence on an Archimedean lattice. Here we explore this phase in the Ising magnet TmB_{4} using high-resolution specific heat (C) and magnetization (M) in the field-temperature plane. We show that the 1/8 FPP is smoothly connected to the antiferromagnetic phase on ramping the field from H=0. Thus, the 1/8 FPP is not a distinct thermodynamic ground state of TmB_{4}. The implication of these results for Heisenberg spins on the SSL is discussed.
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Affiliation(s)
- Jennifer Trinh
- University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Sreemanta Mitra
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Christos Panagopoulos
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Tai Kong
- Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
| | - Paul C Canfield
- Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
| | - Arthur P Ramirez
- University of California Santa Cruz, Santa Cruz, California 95064, USA
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