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He LW, Yu SL, Li JX. Variational Monte Carlo Study of the 1/9-Magnetization Plateau in Kagome Antiferromagnets. PHYSICAL REVIEW LETTERS 2024; 133:096501. [PMID: 39270198 DOI: 10.1103/physrevlett.133.096501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/07/2024] [Accepted: 07/29/2024] [Indexed: 09/15/2024]
Abstract
Motivated by very recent experimental observations of the 1/9-magnetization plateaus in YCu_{3}(OH)_{6+x}Br_{3-x} and YCu_{3}(OD)_{6+x}Br_{3-x}, our study delves into the magnetic-field-induced phase transitions in the nearest-neighbor antiferromagnetic Heisenberg model on the kagome lattice using the variational Monte Carlo technique. We uncover a phase transition from a zero-field Dirac spin liquid to a field-induced magnetically disordered phase that exhibits the 1/9-magnetization plateau. Through a comprehensive analysis encompassing the magnetization distribution, spin correlations, chiral order parameter, topological entanglement entropy, ground-state degeneracy, Chern number, and excitation spectrum, we pinpoint the phase associated with this magnetization plateau as a chiral Z_{3} topological quantum spin liquid and elucidate its diverse physical properties.
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2
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Riberolles SXM, Slade TJ, Han T, Li B, Abernathy DL, Canfield PC, Ueland BG, Orth PP, Ke L, McQueeney RJ. Chiral and flat-band magnetic quasiparticles in ferromagnetic and metallic kagome layers. Nat Commun 2024; 15:1592. [PMID: 38383472 PMCID: PMC10882050 DOI: 10.1038/s41467-024-45841-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 02/02/2024] [Indexed: 02/23/2024] Open
Abstract
Magnetic kagome metals are a promising platform to develop unique quantum transport and optical phenomena caused by the interplay between topological electronic bands, strong correlations, and magnetic order. This interplay may result in exotic quasiparticles that describe the coupled electronic and spin excitations on the frustrated kagome lattice. Here, we observe novel elementary magnetic excitations within the ferromagnetic Mn kagome layers in TbMn6Sn6 using inelastic neutron scattering. We observe sharp, collective acoustic magnons and identify flat-band magnons that are localized to a hexagonal plaquette due to the special geometry of the kagome layer. Surprisingly, we observe another type of elementary magnetic excitation; a chiral magnetic quasiparticle that is also localized on a hexagonal plaquette. The short lifetime of localized flat-band and chiral quasiparticles suggest that they are hybrid excitations that decay into electronic states.
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Affiliation(s)
| | | | - Tianxiong Han
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - Bing Li
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - D L Abernathy
- Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - P C Canfield
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - B G Ueland
- Ames National Laboratory, Ames, IA, 50011, USA
| | - P P Orth
- Ames National Laboratory, Ames, IA, 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - Liqin Ke
- Ames National Laboratory, Ames, IA, 50011, USA
| | - R J McQueeney
- Ames National Laboratory, Ames, IA, 50011, USA.
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA.
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3
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Gen M, Ikeda A, Aoyama K, Jeschke HO, Ishii Y, Ishikawa H, Yajima T, Okamoto Y, Zhou X, Nakamura D, Takeyama S, Kindo K, Matsuda YH, Kohama Y. Signatures of a magnetic superstructure phase induced by ultrahigh magnetic fields in a breathing pyrochlore antiferromagnet. Proc Natl Acad Sci U S A 2023; 120:e2302756120. [PMID: 37549272 PMCID: PMC10438373 DOI: 10.1073/pnas.2302756120] [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: 02/17/2023] [Accepted: 07/01/2023] [Indexed: 08/09/2023] Open
Abstract
The mutual coupling of spin and lattice degrees of freedom is ubiquitous in magnetic materials and potentially creates exotic magnetic states in response to the external magnetic field. Particularly, geometrically frustrated magnets serve as a fertile playground for realizing magnetic superstructure phases. Here, we observe an unconventional two-step magnetostructural transition prior to a half-magnetization plateau in a breathing pyrochlore chromium spinel by means of state-of-the-art magnetization and magnetostriction measurements in ultrahigh magnetic fields available up to 600 T. Considering a microscopic magnetoelastic theory, the intermediate-field phase can be assigned to a magnetic superstructure with a three-dimensional periodic array of 3-up-1-down and canted 2-up-2-down spin molecules. We attribute the emergence of the magnetic superstructure to a unique combination of the strong spin-lattice coupling and large breathing anisotropy.
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Affiliation(s)
- Masaki Gen
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
- RIKEN Center for Emergent Matter Science, Wako, Saitama351-0198, Japan
| | - Akihiko Ikeda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo182-8585, Japan
| | - Kazushi Aoyama
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Osaka560-0043, Japan
| | - Harald O. Jeschke
- Research Institute for Interdisciplinary Science, Okayama University, Okayama700-8530, Japan
| | - Yuto Ishii
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Hajime Ishikawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Takeshi Yajima
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Yoshihiko Okamoto
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Xuguang Zhou
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Daisuke Nakamura
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
- RIKEN Center for Emergent Matter Science, Wako, Saitama351-0198, Japan
| | - Shojiro Takeyama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Koichi Kindo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Yasuhiro H. Matsuda
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
| | - Yoshimitsu Kohama
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba277-8581, Japan
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4
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Karl'ová K, Strečka J, Richter J. Towards lattice-gas description of low-temperature properties above the Haldane and cluster-based Haldane ground states of a mixed spin-(1,1/2) Heisenberg octahedral chain. Phys Rev E 2022; 106:014107. [PMID: 35974518 DOI: 10.1103/physreve.106.014107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/16/2022] [Indexed: 06/15/2023]
Abstract
The rich ground-state phase diagram of the mixed spin-(1,1/2) Heisenberg octahedral chain was previously elaborated from effective mixed-spin Heisenberg chains, which were derived by employing a local conservation of a total spin on square plaquettes of an octahedral chain. Here we present a comprehensive analysis of the thermodynamic properties of this model. In the highly frustrated parameter region the lowest-energy eigenstates of the mixed-spin Heisenberg octahedral chain belong to flat bands, which allow a precise description of low-temperature magnetic properties within the localized-magnon approach exploiting a classical lattice-gas model of hard-core monomers. The present article provides a more comprehensive version of the localized-magnon approach, which extends the range of its validity down to a less frustrated parameter region involving the Haldane and cluster-based Haldane ground states. A comparison between results of the developed localized-magnon theory and accurate numerical methods such as full exact diagonalization and finite-temperature Lanczos technique convincingly evidence that the low-temperature magnetic properties above the Haldane and the cluster-based Haldane ground states can be extracted from a classical lattice-gas model of hard-core monomers and dimers, which is additionally supplemented by a hard-core particle spanned over the whole lattice representing the gapped Haldane phase.
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Affiliation(s)
- Katarína Karl'ová
- Institute of Physics, Faculty of Science, P. J. Šafárik University, 04001 Košice, Slovakia
| | - Jozef Strečka
- Institute of Physics, Faculty of Science, P. J. Šafárik University, 04001 Košice, Slovakia
| | - Johannes Richter
- Institut für Physik, Otto-von-Guericke Universität in Magdeburg, 39016 Magdeburg, Germany
- Max-Planck-Institut für Physik Komplexer Systeme, D-01187 Dresden, Germany
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5
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Schnack J, Schulenburg J, Honecker A, Richter J. Magnon Crystallization in the Kagome Lattice Antiferromagnet. PHYSICAL REVIEW LETTERS 2020; 125:117207. [PMID: 32975976 DOI: 10.1103/physrevlett.125.117207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
We present numerical evidence for the crystallization of magnons below the saturation field at nonzero temperatures for the highly frustrated spin-half kagome Heisenberg antiferromagnet. This phenomenon can be traced back to the existence of independent localized magnons or, equivalently, flatband multimagnon states. We present a loop-gas description of these localized magnons and a phase diagram of this transition, thus providing information for which magnetic fields and temperatures magnon crystallization can be observed experimentally. The emergence of a finite-temperature continuous transition to a magnon crystal is expected to be generic for spin models in dimension D>1 where flatband multimagnon ground states break translational symmetry.
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Affiliation(s)
- Jürgen Schnack
- Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Jörg Schulenburg
- Universitätsrechenzentrum, Universität Magdeburg, D-39016 Magdeburg, Germany
| | - Andreas Honecker
- Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, CY Cergy Paris Université, F-95302 Cergy-Pontoise Cedex, France
| | - Johannes Richter
- Institut für Physik, Universität Magdeburg, P.O. Box 4120, D-39016 Magdeburg, Germany
- Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany
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6
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Strečka J, Ekiz C. Nature of intermediate magnetization plateaus of a spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice resembling a triangulated kagome lattice. Phys Rev E 2020; 102:012132. [PMID: 32794906 DOI: 10.1103/physreve.102.012132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/28/2020] [Indexed: 11/07/2022]
Abstract
The spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice is exactly solved in a magnetic field within the framework of the generalized star-triangle transformation and the method of exact recursion relations. The generalized star-triangle transformation establishes an exact mapping correspondence with the effective spin-1/2 Ising model on a triangular Husimi lattice with a temperature-dependent field, pair and triplet interactions, which is subsequently rigorously treated by making use of exact recursion relations. The ground-state phase diagram of a spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice, which bears a close resemblance with a triangulated kagomé lattice, involves, in total, two classical and three quantum ground states manifested in respective low-temperature magnetization curves as intermediate plateaus at 1/9, 1/3, and 5/9 of the saturation magnetization. It is verified that the fractional magnetization plateaus of quantum nature have character of either dimerized or trimerized ground states. A low-temperature magnetization curve of the spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice resembling a triangulated kagome lattice may exhibit either no intermediate plateau, a single 1/3 plateau, a single 5/9 plateau, or a sequence of 1/9, 1/3, and 5/9 plateaus depending on a character and relative size of two considered coupling constants.
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Affiliation(s)
- Jozef Strečka
- Department of Theoretical Physics and Astrophysics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9, 040 01 Košice, Slovak Republic
| | - Cesur Ekiz
- Department of Physics, Faculty of Science and Letter, Aydın Adnan Menderes University, 09010 Aydın, Turkey
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Hirai D, Yajima T, Nawa K, Kawamura M, Hiroi Z. Anisotropic Triangular Lattice Realized in Rhenium Oxychlorides A 3ReO 5Cl 2 (A = Ba, Sr). Inorg Chem 2020; 59:10025-10033. [PMID: 32584564 DOI: 10.1021/acs.inorgchem.0c01187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the synthesis, crystal structure, and magnetic properties of the two new quantum antiferromagnets A3ReO5Cl2 (A = Sr, Ba). The crystal structure is isostructural with the mineral pinalite Pb3WO5Cl2, in which the Re6+ ion is square pyramidally coordinated by five oxide atoms and forms an anisotropic triangular lattice (ATL) made of S = 1/2 spins. The magnetic interactions J and J' in the ATL are estimated from magnetic susceptibilities to be 19.5 (44.9) and 9.2 (19.3) K, respectively, with J'/J = 0.47 (0.43) for A = Ba (Sr). For each compound, the heat capacity at low temperatures shows a large T-linear component with no signature of long-range magnetic order above 2 K, which suggests a gapless spin liquid state of one-dimensional character of the J chains in spite of the significantly large J' couplings. This is a consequence of one-dimensionalization by geometrical frustration in the ATL magnet; a similar phenomenon has been observed in two compounds with slightly smaller J'/J values: Cs2CuCl4 (J'/J = 0.3) and the related compound Ca3ReO5Cl2 (0.32). Our findings demonstrate that 5d mixed-anion compounds provide a unique opportunity to explore novel quantum magnetism.
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Affiliation(s)
- Daigorou Hirai
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Takeshi Yajima
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Kazuhiro Nawa
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
| | - Mitsuaki Kawamura
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Zenji Hiroi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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Fujihala M, Morita K, Mole R, Mitsuda S, Tohyama T, Yano SI, Yu D, Sota S, Kuwai T, Koda A, Okabe H, Lee H, Itoh S, Hawai T, Masuda T, Sagayama H, Matsuo A, Kindo K, Ohira-Kawamura S, Nakajima K. Gapless spin liquid in a square-kagome lattice antiferromagnet. Nat Commun 2020; 11:3429. [PMID: 32647219 PMCID: PMC7347939 DOI: 10.1038/s41467-020-17235-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 06/19/2020] [Indexed: 11/29/2022] Open
Abstract
Observation of a quantum spin liquid (QSL) state is one of the most important goals in condensed-matter physics, as well as the development of new spintronic devices that support next-generation industries. The QSL in two dimensional quantum spin systems is expected to be due to geometrical magnetic frustration, and thus a kagome-based lattice is the most probable playground for QSL. Here, we report the first experimental results of the QSL state on a square-kagome quantum antiferromagnet, KCu6AlBiO4(SO4)5Cl. Comprehensive experimental studies via magnetic susceptibility, magnetisation, heat capacity, muon spin relaxation (μSR), and inelastic neutron scattering (INS) measurements reveal the formation of a gapless QSL at very low temperatures close to the ground state. The QSL behavior cannot be explained fully by a frustrated Heisenberg model with nearest-neighbor exchange interactions, providing a theoretical challenge to unveil the nature of the QSL state.
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Affiliation(s)
- Masayoshi Fujihala
- Tokyo University of Science, Department of Physics, Tokyo, 162-8601, Japan.
| | - Katsuhiro Morita
- Tokyo University of Science, Department of Applied Physics, Tokyo, 125-8585, Japan.
| | - Richard Mole
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2232, Australia
| | - Setsuo Mitsuda
- Tokyo University of Science, Department of Physics, Tokyo, 162-8601, Japan
| | - Takami Tohyama
- Tokyo University of Science, Department of Applied Physics, Tokyo, 125-8585, Japan
| | - Shin-Ichiro Yano
- National Synchrotron Radiation Research Center, Hsinchu, 30077, Taiwan
| | - Dehong Yu
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2232, Australia
| | - Shigetoshi Sota
- Computational Materials Science Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
| | - Tomohiko Kuwai
- Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555, Japan
| | - Akihiro Koda
- Muon Science Laboratory and Condensed Matter Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organisation, 1-1 Oho, Tsukuba, 305-0801, Japan
| | - Hirotaka Okabe
- Muon Science Laboratory and Condensed Matter Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organisation, 1-1 Oho, Tsukuba, 305-0801, Japan
| | - Hua Lee
- Muon Science Laboratory and Condensed Matter Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organisation, 1-1 Oho, Tsukuba, 305-0801, Japan
| | - Shinichi Itoh
- Neutron Science Division, Institute of Materials Structure Science, High Energy Accelerator Research Organisation, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Takafumi Hawai
- Neutron Science Division, Institute of Materials Structure Science, High Energy Accelerator Research Organisation, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Takatsugu Masuda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Hajime Sagayama
- Synchrotron Radiation Science Division 1 and Center for Integrative Quantum Beam Science, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Akira Matsuo
- International MegaGauss Science Laboratory, Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Koichi Kindo
- International MegaGauss Science Laboratory, Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, 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
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Hiroi Z, Ishikawa H, Yoshida H, Yamaura JI, Okamoto Y. Orbital Transitions and Frustrated Magnetism in the Kagome-Type Copper Mineral Volborthite. Inorg Chem 2019; 58:11949-11960. [PMID: 31247871 DOI: 10.1021/acs.inorgchem.9b01165] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Volborthite Cu3V2O7(OH)2·2H2O is a copper mineral that materializes a two-dimensional quantum magnet comprising a kagome net of spin-1/2 Cu2+ ions. We prepared single crystals of volborthite using hydrothermal conditions and investigated their crystal structures and magnetic properties. Unusual orbital "switching" and "flipping" transitions were observed: in the former type of transition (switching), the Cu 3d orbital occupied by an unpaired electron changes between the d(3z2-r2) and d(x2-y2) types, and in the latter type of transition (flipping), the d(x2-y2)-type orbitals change their directions. Their origin is ascribed to variations in the orientation of water molecules in the gap between the kagome layers and the accompanying changes of hydrogen bonding. These orbital transitions dramatically modify the magnetic interactions between Cu2+ spins, from the anisotropic kagome type to the formation of spin trimers over the kagome net. The effective spin 1/2 generated on the trimers exhibits a frustrated magnetism, resulting in a rich phase diagram in the magnetic fields. Volborthite is a unique compound showing an exceptional interplay between the orbital and spin degrees of freedom.
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Affiliation(s)
- Zenji Hiroi
- Institute for Solid State Physics , University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
| | - Hajime Ishikawa
- Institute for Solid State Physics , University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
| | - Hiroyuki Yoshida
- Department of Physics, Faculty of Science , Hokkaido University , Sapporo 060-0810 , Japan
| | - Jun-Ichi Yamaura
- Materials Research Center for Element Strategy , Tokyo Institute of Technology , Yokohama , Kanagawa 226-8503 , Japan
| | - Yoshihiko Okamoto
- Department of Applied Physics , Nagoya University , Nagoya 464-8603 , Japan
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