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Zhang S, Yang X, Wooten BL, Bag R, Yadav L, Moore CE, Parida S, Trivedi N, Lu Y, Heremans JP, Haravifard S, Wu Y. Two-Dimensional Cobalt(II) Benzoquinone Frameworks for Putative Kitaev Quantum Spin Liquid Candidates. J Am Chem Soc 2024; 146:15061-15069. [PMID: 38787332 DOI: 10.1021/jacs.3c14537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The realization and discovery of quantum spin liquid (QSL) candidate materials are crucial for exploring exotic quantum phenomena and applications associated with QSLs. Most existing metal-organic two-dimensional (2D) quantum spin liquid candidates have structures with spins arranged on the triangular or kagome lattices, whereas honeycomb-structured metal-organic compounds with QSL characteristics are rare. Here, we report the use of 2,5-dihydroxy-1,4-benzoquinone (X2dhbq, X = Cl, Br, H) as the linkers to construct cobalt(II) honeycomb lattices (NEt4)2[Co2(X2dhbq)3] as promising Kitaev-type QSL candidate materials. The high-spin d7 Co2+ has pseudospin-1/2 ground-state doublets, and benzoquinone-based linkers not only provide two separate superexchange pathways that create bond-dependent frustrated interactions but also allow for chemical tunability to mediate magnetic coupling. Our magnetization data show antiferromagnetic interactions between neighboring metal centers with Weiss constants from -5.1 to -8.5 K depending on the X functional group in X2dhbq linkers (X = Cl, Br, H). No magnetic transition or spin freezing could be observed down to 2 K. Low-temperature susceptibility (down to 0.3 K) and specific heat (down to 0.055 K) of (NEt4)2[Co2(H2dhbq)3] were further analyzed. Heat capacity measurements confirmed no long-range order down to 0.055 K, evidenced by the broad peak instead of the λ-like anomaly. Our results indicate that these 2D cobalt benzoquinone frameworks are promising Kitaev QSL candidates with chemical tunability through ligands that can vary the magnetic coupling and frustration.
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Affiliation(s)
- Songwei Zhang
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xu Yang
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Brandi L Wooten
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Rabindranath Bag
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Lalit Yadav
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Curtis E Moore
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Smrutimedha Parida
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Nandini Trivedi
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yuanming Lu
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Joseph P Heremans
- Department of Mechanical & Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sara Haravifard
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Yiying Wu
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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2
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Darie C, Bordet P, Viaud M, Guillot-Deudon C, Deniard P, Gautron E, Colin C, Porcher F, Berlanda G, Bert F, Mendels P, Payen C. Two new cubic perovskite oxides Ba3CoSb2O9 and Ba2SrCoSb2O9: Syntheses, crystal structures and magnetic properties. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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3
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Kumar J, Dey K, Panja SN, Nair S. Anomalous dielectric response in the triple perovskite ruthenate Ba 3BiRu 2O 9. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:465401. [PMID: 36063793 DOI: 10.1088/1361-648x/ac8f7c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/05/2022] [Indexed: 06/15/2023]
Abstract
We have investigated the magnetic, dielectric and thermal properties of theSRu= 1 magnetic dimer Ba3BiRu2O9, which is known to exhibit a spin-gap opening in conjunction with a first-order magneto-elastic phase transition at ∼175 K. Above the spin-gap temperature, the temperature dependence dielectric constant shows a peak like feature with pronounced frequency dependence. The critical slowing down behavior of this frequency dispersion suggests that a ferroelectric relaxor like electrical glassy state exists above the spin-gap opening temperature regime. The extermination of frequency dispersion-right at the magneto-elastic phase transition, is suggestive of a strong coupling between the lattice and charge-spin degrees of freedom in this triple perovskite system.
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Affiliation(s)
- Jitender Kumar
- Department of Physics, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune 411008, India
| | - Kaustav Dey
- Department of Physics, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune 411008, India
| | - Soumendra Nath Panja
- Department of Physics, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune 411008, India
| | - Sunil Nair
- Department of Physics, Indian Institute of Science Education and Research, Dr Homi Bhabha Road, Pune 411008, India
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4
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Mandujano HC, Gonzalez SL, Episcopo N, Sitharaman U, Poudel N, Gofryk K, Garay YE, Lopez JA, Zhang Q, Calder S, Nair HS. Absence of long-range magnetic order in lithium-containing honeycombs in the Li-Cr-Sb(Te)-O phases. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:295802. [PMID: 33971639 DOI: 10.1088/1361-648x/abff90] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Li3((LiCr)(Te/Sb))O6compounds where Cr atoms along with Li and Te or Sb are part of a honeycomb and are studied using magnetic susceptibility, specific heat, x-ray photoelectron spectroscopy and neutron diffraction. The oxides stoichiometries as determined from the neutron diffraction studies are Li4.47Cr0.53TeO6and Li3.88Cr1.12SbO6with a stable oxidation state of +3 for Cr. Both the compounds crystallize in space groupC2/mwith intermixing of cations at the 4gsites leaving the 2asites preferentially for Te or Sb. Again, the Li+ions alone predominantly occur in the interlayer sites. Both the compounds show a broad anomaly in specific heat at 8 K, which is robust against 8 T. A corresponding anomaly is absent in the magnetic susceptibility but recovers from its derivative, dχ(T)/dT. We ascertain the magnetic anomaly temperatures (Ta) of Li4.47Cr0.53TeO6and Li3.88Cr1.12SbO6as 5.9 K and 6.7 K respectively from specific heat. Although the physical properties indicated a low temperature anomaly, neutron diffraction data did not reveal a magnetic signal or a structural anomaly down to 1.5 K. This rules out a conventional long-range ordered magnetic ground state in either compounds. Combining the results from specific heat, neutron diffraction and electron paramagnetic resonance, we put forth a scenario of depleted honeycomb lattice of Cr3+with predominant short-range magnetic correlations as the magnetic ground states of the title compounds.
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Affiliation(s)
- H Cein Mandujano
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
| | - Sandra L Gonzalez
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
| | - Nathan Episcopo
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
| | - Uma Sitharaman
- Department of Chemistry, University of Delhi, Delhi-110007, India
| | - Narayan Poudel
- Idaho National Laboratory, Idaho Falls, ID 83415, United States of America
| | - Krzysztof Gofryk
- Idaho National Laboratory, Idaho Falls, ID 83415, United States of America
| | - Yahir E Garay
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
| | - Jorge A Lopez
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
| | - Qiang Zhang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States of America
| | - Stuart Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States of America
| | - Harikrishnan S Nair
- Department of Physics, 500 W University Ave, University of Texas at El Paso, El Paso, TX 79968, United States of America
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5
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Broholm C, Cava RJ, Kivelson SA, Nocera DG, Norman MR, Senthil T. Quantum spin liquids. Science 2020; 367:367/6475/eaay0668. [DOI: 10.1126/science.aay0668] [Citation(s) in RCA: 271] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- C. Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - R. J. Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - S. A. Kivelson
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - D. G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - M. R. Norman
- Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - T. Senthil
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Shimura Y, Zhang Q, Zeng B, Rhodes D, Schönemann R, Tsujimoto M, Matsumoto Y, Sakai A, Sakakibara T, Araki K, Zheng W, Zhou Q, Balicas L, Nakatsuji S. Giant Anisotropic Magnetoresistance due to Purely Orbital Rearrangement in the Quadrupolar Heavy Fermion Superconductor PrV_{2}Al_{20}. PHYSICAL REVIEW LETTERS 2019; 122:256601. [PMID: 31347904 DOI: 10.1103/physrevlett.122.256601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Indexed: 06/10/2023]
Abstract
We report the discovery of giant and anisotropic magnetoresistance due to the orbital rearrangement in a non magnetic correlated metal. In particular, we measured the magnetoresistance under fields up to 31.4 T in the cubic Pr-based heavy fermion superconductor PrV_{2}Al_{20} with a non magnetic Γ_{3} doublet ground state, exhibiting antiferroquadrupole ordering below 0.7 K. For the [100] direction, we find that the high-field phase appears between 12 and 25 T, accompanied by a large jump at 12 T in the magnetoresistance (ΔMR∼100%) and in the anisotropic magnetoresistivity ratio by ∼20%. These observations indicate that the strong hybridization between the conduction electrons and anisotropic quadrupole moments leads to the Fermi surface reconstruction upon crossing the field-induced antiferroquadrupole (orbital) rearrangement.
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Affiliation(s)
- Yasuyuki Shimura
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima 739-8530, Japan
| | - Qiu Zhang
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Bin Zeng
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Daniel Rhodes
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Rico Schönemann
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Masaki Tsujimoto
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Yosuke Matsumoto
- Department of Quantum Materials, Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569, Germany
| | - Akito Sakai
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Toshiro Sakakibara
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Koji Araki
- Department of Applied Physics, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
| | - Wenkai Zheng
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Qiong Zhou
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Luis Balicas
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Satoru Nakatsuji
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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7
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Man H, Halim M, Sawa H, Hagiwara M, Wakabayashi Y, Nakatsuji S. Spin-orbital entangled liquid state in the copper oxide Ba 3CuSb 2O 9. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:443002. [PMID: 30210058 DOI: 10.1088/1361-648x/aae106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Structure with orbital degeneracy is unstable toward spontaneous distortion. Such orbital correlation usually has a much higher energy scale than spins, and therefore, magnetic transition takes place at a much lower temperature, almost independently from orbital ordering. However, when the energy scales of orbitals and spins meet, there is a possibility of spin-orbital entanglement that would stabilize novel ground state such as spin-orbital liquid and random singlet state. Here we review on such a novel spin-orbital magnetism found in the hexagonal perovskite oxide Ba3CuSb2O9, which hosts a self-organized honeycomblike short-range order of a strong Jahn-Teller ion Cu2+. Comprehensive structural and magnetic measurements have revealed that the system has neither magnetic nor Jahn-Teller transition down to the lowest temperatures, and Cu spins and orbitals retain the hexagonal symmetry and paramagnetic state. Various macroscopic and microscopic measurements all indicate that spins and orbitals remain fluctuating down to low temperatures without freezing, forming a spin-orbital entangled liquid state.
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Affiliation(s)
- Huiyuan Man
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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8
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Abstract
Spin is an intrinsic quantum mechanical property of fundamental particles including the electron. The spin property is intimately related to electronic and optical properties of molecules and materials. The combination of spin (magnetic), electronic, and optical properties of materials, such as organometal halide perovskites (OMHP), has attracted increasing attention, which has led to a new field termed spin-optotronics based on all three key properties. This growing field has implications in emerging technological applications across disciplines, including photonics, electronics, spintronics, quantum computation, and information storage. This Perspective provides a brief introduction to this field from both experimental and computational aspects, with a focus on the effect of spin on charge carrier dynamics in OMHP, a class of materials with novel properties and promising applications in a number of fields. For instance, recent studies have demonstrated the use of ultrafast laser techniques in probing the fundamental charge carrier dynamics in relation to spin properties. Because of strong spin-orbit coupling (SOC) and broken inversion symmetry that result in Rashba and Dresselhaus effects, OMHP are considered ideal for manipulating spin states for spin-optotronics applications. In the meantime, on the basis of first-principles calculations and effective model Hamiltonians, the Rashba splitting in locally polarized domains can result in spin-forbidden recombination with significantly slow transition rate due to the mismatch of spin and momentum. We summarize the state-of-the-art first-principles methods and their current limitations for ultrafast charge and spin dynamics for realistic solid-state systems in general. To conclude, we note some promising future research and development directions for both experimental and theoretical ultrafast spin dynamics studies of OMHP.
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Affiliation(s)
- Yuan Ping
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Jin Zhong Zhang
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
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9
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Yamamoto TD, Taniguchi H, Terasaki I. Dynamical coupling of dilute magnetic impurities with quantum spin liquid state in the S = 3/2 dimer compound Ba 3ZnRu 2O 9. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:355801. [PMID: 30043759 DOI: 10.1088/1361-648x/aad5ac] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have investigated the dilute magnetic impurity effect on the magnetic properties of a quantum spin liquid candidate Ba3ZnRu2O9 and a spin gapped compound Ba3CaRu2O9. The magnetic ground state of each compound stands against 2% substitution of magnetic impurities for Zn or Ca. We have found that the magnetic response of these impurities, which behave as paramagnetic spins, depends on the host materials and the difference of the two manifests itself in the Weiss temperature, which can hardly be explained by the dilute magnetic impurities alone in the case of Ba3ZnRu2O9. We consider a contribution from the Ru5+ ions which would appear only in the substituted Ba3ZnRu2O9 and discuss a possible physical meaning of the observed Weiss temperature.
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10
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Yamada MG, Oshikawa M, Jackeli G. Emergent SU(4) Symmetry in α-ZrCl_{3} and Crystalline Spin-Orbital Liquids. PHYSICAL REVIEW LETTERS 2018; 121:097201. [PMID: 30230904 DOI: 10.1103/physrevlett.121.097201] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 07/16/2018] [Indexed: 06/08/2023]
Abstract
While the enhancement of spin-space symmetry from the usual SU(2) to SU(N) is promising for finding nontrivial quantum spin liquids, its realization in magnetic materials remains challenging. Here, we propose a new mechanism by which SU(4) symmetry emerges in the strong spin-orbit coupling limit. In d^{1} transition metal compounds with edge-sharing anion octahedra, the spin-orbit coupling gives rise to strongly bond-dependent and apparently SU(4)-breaking hopping between the J_{eff}=3/2 quartets. However, in the honeycomb structure, a gauge transformation maps the system to an SU(4)-symmetric Hubbard model. In the strong repulsion limit at quarter filling, as realized in α-ZrCl_{3}, the low-energy effective model is the SU(4) Heisenberg model on the honeycomb lattice, which cannot have a trivial gapped ground state and is expected to host a gapless spin-orbital liquid. By generalizing this model to other three-dimensional lattices, we also propose crystalline spin-orbital liquids protected by this emergent SU(4) symmetry and space group symmetries.
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Affiliation(s)
- Masahiko G Yamada
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Masaki Oshikawa
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - George Jackeli
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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11
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Gunasekera J, Dahal A, Chen Y, Rodriguez‐Rivera JA, Harriger LW, Thomas S, Heitmann TW, Dugaev V, Ernst A, Singh DK. Quantum Magnetic Properties in Perovskite with Anderson Localized Artificial Spin-1/2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1700978. [PMID: 29876219 PMCID: PMC5980209 DOI: 10.1002/advs.201700978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/29/2018] [Indexed: 06/08/2023]
Abstract
Quantum magnetic properties in a geometrically frustrated lattice of spin-1/2 magnet, such as quantum spin liquid or solid and the associated spin fractionalization, are considered key in developing a new phase of matter. The feasibility of observing the quantum magnetic properties, usually found in geometrically frustrated lattice of spin-1/2 magnet, in a perovskite material with controlled disorder is demonstrated. It is found that the controlled chemical disorder, due to the chemical substitution of Ru ions by Co-ions, in a simple perovskite CaRuO3 creates a random prototype configuration of artificial spin-1/2 that forms dimer pairs between the nearest and further away ions. The localization of the Co impurity in the Ru matrix is analyzed using the Anderson localization formulation. The dimers of artificial spin-1/2, due to the localization of Co impurities, exhibit singlet-to-triplet excitation at low temperature without any ordered spin correlation. The localized gapped excitation evolves into a gapless quasi-continuum as dimer pairs break and create freely fluctuating fractionalized spins at high temperature. Together, these properties hint at a new quantum magnetic state with strong resemblance to the resonance valence bond system.
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Affiliation(s)
- Jagath Gunasekera
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211‐7010USA
| | - Ashutosh Dahal
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211‐7010USA
| | - Yiyao Chen
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211‐7010USA
| | - Jose A. Rodriguez‐Rivera
- NIST Center for Neutron ResearchGaithersburgMD20878USA
- Department of Materials Science and EngineeringUniversity of MarylandCollege ParkMD20742USA
| | | | - Stefan Thomas
- Max‐Planck‐Institut für MikrostrukturphysikWeinberg 206120HalleGermany
| | | | - Vitalii Dugaev
- Department of Physics and Medical EngineeringRzeszów University of Technology35‐959RzeszówPoland
| | - Arthur Ernst
- Max‐Planck‐Institut für MikrostrukturphysikWeinberg 206120HalleGermany
- Institut für Theoretische PhysikJohannes Kepler Universität4040LinzAustria
| | - Deepak K. Singh
- Department of Physics and AstronomyUniversity of MissouriColumbiaMO65211‐7010USA
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12
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Zhang B, Baker PJ, Zhang Y, Wang D, Wang Z, Su S, Zhu D, Pratt FL. Quantum Spin Liquid from a Three-Dimensional Copper-Oxalate Framework. J Am Chem Soc 2017; 140:122-125. [DOI: 10.1021/jacs.7b11179] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bin Zhang
- Organic Solid Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, CMS & BNLMS, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Peter J. Baker
- ISIS
Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Yan Zhang
- Institute
of Condensed Matter and Material Physics, Department of Physics, Peking University, Beijing 100871, People’s Republic of China
| | - Dongwei Wang
- CAS
Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People’s Republic of China
| | - Zheming Wang
- State
Key Laboratory of Rare Earth Materials Chemistry and Applications,
BNLMS, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Shaokui Su
- Beijing National
Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Daoben Zhu
- Organic Solid Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, CMS & BNLMS, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Francis L. Pratt
- ISIS
Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
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Shimozawa M, Hashimoto K, Ueda A, Suzuki Y, Sugii K, Yamada S, Imai Y, Kobayashi R, Itoh K, Iguchi S, Naka M, Ishihara S, Mori H, Sasaki T, Yamashita M. Quantum-disordered state of magnetic and electric dipoles in an organic Mott system. Nat Commun 2017; 8:1821. [PMID: 29180819 PMCID: PMC5703743 DOI: 10.1038/s41467-017-01849-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 10/18/2017] [Indexed: 11/24/2022] Open
Abstract
Strongly enhanced quantum fluctuations often lead to a rich variety of quantum-disordered states. Developing approaches to enhance quantum fluctuations may open paths to realize even more fascinating quantum states. Here, we demonstrate that a coupling of localized spins with the zero-point motion of hydrogen atoms, that is, proton fluctuations in a hydrogen-bonded organic Mott insulator provides a different class of quantum spin liquids (QSLs). We find that divergent dielectric behavior associated with the approach to hydrogen-bond order is suppressed by the quantum proton fluctuations, resulting in a quantum paraelectric (QPE) state. Furthermore, our thermal-transport measurements reveal that a QSL state with gapless spin excitations rapidly emerges upon entering the QPE state. These findings indicate that the quantum proton fluctuations give rise to a QSL—a quantum-disordered state of magnetic and electric dipoles—through the coupling between the electron and proton degrees of freedom. The organic material κ-H3(Cat-EDT-TTF)2 has been suggested to exhibit a quantum spin liquid phase in which quantum fluctuations prevent the formation of magnetic order. Here, the authors show that this may be a result of fluctuations of hydrogen atoms, rather than more conventional geometric frustration.
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Affiliation(s)
- M Shimozawa
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan.
| | - K Hashimoto
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan.
| | - A Ueda
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Y Suzuki
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - K Sugii
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - S Yamada
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Y Imai
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - R Kobayashi
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan
| | - K Itoh
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan
| | - S Iguchi
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan
| | - M Naka
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan.,Waseda Institute for Advanced Study, Waseda University, Shinjuku, Tokyo, 169-8050, Japan
| | - S Ishihara
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan
| | - H Mori
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - T Sasaki
- Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, 980-8577, Japan
| | - M Yamashita
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
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14
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Yamaguchi H, Okada M, Kono Y, Kittaka S, Sakakibara T, Okabe T, Iwasaki Y, Hosokoshi Y. Randomness-induced quantum spin liquid on honeycomb lattice. Sci Rep 2017; 7:16144. [PMID: 29170459 PMCID: PMC5701036 DOI: 10.1038/s41598-017-16431-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/03/2017] [Indexed: 11/08/2022] Open
Abstract
Quantum entanglement in magnetic materials is expected to yield a quantum spin liquid (QSL), in which strong quantum fluctuations prevent magnetic ordering even at zero temperature. This topic has been one of the primary focuses of condensed-matter science since Anderson first proposed the resonating valence bond state in a certain spin-1/2 frustrated magnet in 1973. Since then, several candidate materials featuring frustration, such as triangular and kagome lattices, have been reported to exhibit liquid-like behavior. However, the mechanisms that stabilize the liquid-like states have remained elusive. Here, we present a QSL state in a spin-1/2 honeycomb lattice with randomness in the exchange interaction. That is, we successfully introduce randomness into the organic radial-based complex and realize a random-singlet (RS) state (or valence bond glass). All magnetic and thermodynamic experimental results indicate the liquid-like behaviors, which are consistent with those expected in the RS state. Our results suggest that the randomness or inhomogeneity in the actual systems stabilize the RS state and yield liquid-like behavior.
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Affiliation(s)
- Hironori Yamaguchi
- Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan.
| | - Masataka Okada
- Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan
| | - Yohei Kono
- Institute for Solid State Physics, The University of Tokyo, Chiba, 277-8581, Japan
| | - Shunichiro Kittaka
- Institute for Solid State Physics, The University of Tokyo, Chiba, 277-8581, Japan
| | - Toshiro Sakakibara
- Institute for Solid State Physics, The University of Tokyo, Chiba, 277-8581, Japan
| | - Toshiki Okabe
- Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan
| | - Yoshiki Iwasaki
- Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan
| | - Yuko Hosokoshi
- Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan
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15
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Li J, Jiang P, Gao W, Cong R, Yang T. Chemical Substitution-Induced and Competitive Formation of 6H and 3C Perovskite Structures in Ba3–xSrxZnSb2O9: The Coexistence of Two Perovskites in 0.3 ≤ x ≤ 1.0. Inorg Chem 2017; 56:14335-14344. [DOI: 10.1021/acs.inorgchem.7b02429] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Li
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China
| | - Pengfei Jiang
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China
| | - Wenliang Gao
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China
| | - Rihong Cong
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China
| | - Tao Yang
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, P. R. China
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16
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Doi Y, Wakeshima M, Tezuka K, Shan YJ, Ohoyama K, Lee S, Torii S, Kamiyama T, Hinatsu Y. Crystal structures, magnetic properties, and DFT calculation of B-site defected 12L-perovskites Ba 2La 2MW 2O 12 (M = Mn, Co, Ni, Zn). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:365802. [PMID: 28661405 DOI: 10.1088/1361-648x/aa7c9b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The synthesis, crystal structures and magnetic properties of Ba2La2MW2O12 (M = Mn, Co, Ni, Zn) were investigated. They crystallize in the 12-layer polytype of the perovskite structure with a regular cation defect in the B-site. The results of neutron diffraction measurements reveal that they adopt a rhombohedral structure with a space group R - 3 and have a cation ordering between Ba and La ions in the A-site. In these compounds, the magnetic M ions form the 2D triangular lattice. From the results of magnetic measurements, the ferromagnetic ordering of M2+ ions for M = Co (T C = 1.3 K) and Ni (6.2 K) and the paramagnetic behavior (T > 1.8 K) with an antiferromagnetic interaction for M = Mn are observed. From the DFT calculation, their band structures and magnetic interactions are discussed.
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Affiliation(s)
- Yoshihiro Doi
- Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
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17
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Structure and interstitial iodide migration in hybrid perovskite methylammonium lead iodide. Nat Commun 2017; 8:15152. [PMID: 28492242 PMCID: PMC5437276 DOI: 10.1038/ncomms15152] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/02/2017] [Indexed: 01/12/2023] Open
Abstract
Hybrid perovskites form an emerging family of exceptional light harvesting compounds. However, the mechanism underpinning their photovoltaic effect is still far from understood, which is impeded by a lack of clarity on their structures. Here we show that iodide ions in the methylammonium lead iodide migrate via interstitial sites at temperatures above 280 K. This coincides with temperature dependent static distortions resulting in pseudocubic local symmetry. Based on bond distance analysis, the migrating and distorted iodines are at lengths consistent with the formation of I2 molecules, suggesting a 2I−→I2+2e− redox couple. The actual formula of this compound is thus (CH3NH3)PbI3−2x(I2)x where x∼0.007 at room temperature. A crucial feature of the tetragonal structure is that the methylammonium ions do not sit centrally in the A-site cavity, but disordered around two off-centre orientations that facilitate the interstitial ion migration via a gate opening mechanism. The mechanism underpinning the photovoltaic effect in hybrid perovskite solar cells has remained unclear. Here, Green and co-workers suggest that iodide ions in methylammonium lead iodide perovskite migrate via interstitial sites and undergo a redox reaction to form molecular iodine and free electrons.
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18
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Sugii K, Shimozawa M, Watanabe D, Suzuki Y, Halim M, Kimata M, Matsumoto Y, Nakatsuji S, Yamashita M. Thermal Hall Effect in a Phonon-Glass Ba_{3}CuSb_{2}O_{9}. PHYSICAL REVIEW LETTERS 2017; 118:145902. [PMID: 28430491 DOI: 10.1103/physrevlett.118.145902] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Indexed: 06/07/2023]
Abstract
A distinct thermal Hall signal is observed in a quantum spin liquid candidate Ba_{3}CuSb_{2}O_{9}. The transverse thermal conductivity shows a power-law temperature dependence below 50 K, where a spin gap opens. We suggest that because of the very low longitudinal thermal conductivity and the thermal Hall signals, a phonon Hall effect is induced by strong phonon scattering of orphan Cu^{2+} spins formed in the random domains of the Cu^{2+}-Sb^{5+} dumbbells in Ba_{3}CuSb_{2}O_{9}.
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Affiliation(s)
- K Sugii
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - M Shimozawa
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - D Watanabe
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Y Suzuki
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - M Halim
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - M Kimata
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Y Matsumoto
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - S Nakatsuji
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - M Yamashita
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
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19
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Nirmala R, Jang KH, Sim H, Cho H, Lee J, Yang NG, Lee S, Ibberson RM, Kakurai K, Matsuda M, Cheong SW, Gapontsev VV, Streltsov SV, Park JG. Spin glass behavior in frustrated quantum spin system CuAl 2O 4 with a possible orbital liquid state. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:13LT01. [PMID: 28140356 DOI: 10.1088/1361-648x/aa5c72] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
CuAl2O4 is a normal spinel oxide having quantum spin, S = 1/2 for Cu2+. It is a rather unique feature that the Cu2+ ions of CuAl2O4 sit at a tetrahedral position, not like the usual octahedral position for many oxides. At low temperatures, it exhibits all the thermodynamic evidence of a quantum spin glass. For example, the polycrystalline CuAl2O4 shows a cusp centered at ~2 K in the low-field dc magnetization data and a clear frequency dependence in the ac magnetic susceptibility while it displays logarithmic relaxation behavior in a time dependence of the magnetization. At the same time, there is a peak at ~2.3 K in the heat capacity, which shifts towards a higher temperature with magnetic fields. On the other hand, there is no evidence of new superlattice peaks in the high-resolution neutron powder diffraction data when cooled from 40 to 0.4 K. This implies that there is no long-ranged magnetic order down to 0.4 K, thus confirming a spin glass-like ground state for CuAl2O4. Interestingly, there is no sign of structural distortion either although Cu2+ is a Jahn-Teller active ion. Thus, we claim that an orbital liquid state is the most likely ground state in CuAl2O4. Of further interest, it also exhibits a large frustration parameter, f = |θ CW/T m| ~ 67, one of the largest values reported for spinel oxides. Our observations suggest that CuAl2O4 should be a rare example of a frustrated quantum spin glass with a good candidate for an orbital liquid state.
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Affiliation(s)
- R Nirmala
- Center for Strongly Correlated Materials Research, Seoul National University, Seoul 08826, Korea. Department of Physics, Indian Institute of Technology Madras, Chennai 600 036, India. Department of Physics, Sungkyunkwan University, Suwon 16419, Korea
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20
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Thygesen PMM, Paddison JAM, Zhang R, Beyer KA, Chapman KW, Playford HY, Tucker MG, Keen DA, Hayward MA, Goodwin AL. Orbital Dimer Model for the Spin-Glass State in Y_{2}Mo_{2}O_{7}. PHYSICAL REVIEW LETTERS 2017; 118:067201. [PMID: 28234510 DOI: 10.1103/physrevlett.118.067201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Indexed: 06/06/2023]
Abstract
The formation of a spin glass generally requires that magnetic exchange interactions are both frustrated and disordered. Consequently, the origin of spin-glass behavior in Y_{2}Mo_{2}O_{7}-in which magnetic Mo^{4+} ions occupy a frustrated pyrochlore lattice with minimal compositional disorder-has been a longstanding question. Here, we use neutron and x-ray pair-distribution function (PDF) analysis to develop a disorder model that resolves apparent incompatibilities between previously reported PDF, extended x-ray-absorption fine structure spectroscopy, and NMR studies, and provides a new and physical explanation of the exchange disorder responsible for spin-glass formation. We show that Mo^{4+} ions displace according to a local "two-in-two-out" rule on each Mo_{4} tetrahedron, driven by orbital dimerization of Jahn-Teller active Mo^{4+} ions. Long-range orbital order is prevented by the macroscopic degeneracy of dimer coverings permitted by the pyrochlore lattice. Cooperative O^{2-} displacements yield a distribution of Mo-O-Mo angles, which in turn introduces disorder into magnetic interactions. Our study demonstrates experimentally how frustration of atomic displacements can assume the role of compositional disorder in driving a spin-glass transition.
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Affiliation(s)
- Peter M M Thygesen
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Joseph A M Paddison
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332-0430, USA
| | - Ronghuan Zhang
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Kevin A Beyer
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Karena W Chapman
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Helen Y Playford
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Matthew G Tucker
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
- Diamond Light Source, Chilton, Oxfordshire OX11 0DE, United Kingdom
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - David A Keen
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Michael A Hayward
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Andrew L Goodwin
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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21
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Sheckelton JP, Plumb KW, Trump BA, Broholm CL, McQueen TM. Rearrangement of van der Waals stacking and formation of a singlet state at T = 90 K in a cluster magnet. Inorg Chem Front 2017. [DOI: 10.1039/c6qi00470a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A change of van der Waals stacking occurs spontaneously at 90 K in a cluster magnet.
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Affiliation(s)
- John P. Sheckelton
- Department of Chemistry
- The Johns Hopkins University
- Baltimore
- USA
- Institute for Quantum Matter and Department of Physics and Astronomy
| | - Kemp W. Plumb
- Institute for Quantum Matter and Department of Physics and Astronomy
- The Johns Hopkins University
- Baltimore
- USA
| | - Benjamin A. Trump
- Department of Chemistry
- The Johns Hopkins University
- Baltimore
- USA
- Institute for Quantum Matter and Department of Physics and Astronomy
| | - Collin L. Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy
- The Johns Hopkins University
- Baltimore
- USA
- Department of Materials Science and Engineering
| | - Tyrel M. McQueen
- Department of Chemistry
- The Johns Hopkins University
- Baltimore
- USA
- Institute for Quantum Matter and Department of Physics and Astronomy
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22
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Designing Quantum Spin-Orbital Liquids in Artificial Mott Insulators. Sci Rep 2016; 6:31737. [PMID: 27553516 PMCID: PMC4995463 DOI: 10.1038/srep31737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/25/2016] [Indexed: 11/10/2022] Open
Abstract
Quantum spin-orbital liquids are elusive strongly correlated states of matter that emerge from quantum frustration between spin and orbital degrees of freedom. A promising route towards the observation of those states is the creation of artificial Mott insulators where antiferromagnetic correlations between spins and orbitals can be designed. We show that Coulomb impurity lattices on the surface of gapped honeycomb substrates, such as graphene on SiC, can be used to simulate SU(4) symmetric spin-orbital lattice models. We exploit the property that massive Dirac fermions form mid-gap bound states with spin and valley degeneracies in the vicinity of a Coulomb impurity. Due to electronic repulsion, the antiferromagnetic correlations of the impurity lattice are driven by a super-exchange interaction with SU(4) symmetry, which emerges from the bound states degeneracy at quarter filling. We propose that quantum spin-orbital liquids can be engineered in artificially designed solid-state systems at vastly higher temperatures than achievable in optical lattices with cold atoms. We discuss the experimental setup and possible scenarios for candidate quantum spin-liquids in Coulomb impurity lattices of various geometries.
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23
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Smerald A, Korshunov S, Mila F. Topological Aspects of Symmetry Breaking in Triangular-Lattice Ising Antiferromagnets. PHYSICAL REVIEW LETTERS 2016; 116:197201. [PMID: 27232039 DOI: 10.1103/physrevlett.116.197201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 06/05/2023]
Abstract
Using a specially designed Monte Carlo algorithm with directed loops, we investigate the triangular lattice Ising antiferromagnet with coupling beyond the nearest neighbors. We show that the first-order transition from the stripe state to the paramagnet can be split, giving rise to an intermediate nematic phase in which algebraic correlations coexist with a broken symmetry. Furthermore, we demonstrate the emergence of several properties of a more topological nature such as fractional edge excitations in the stripe state, the proliferation of double domain walls in the nematic phase, and the Kasteleyn transition between them. Experimental implications are briefly discussed.
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Affiliation(s)
- Andrew Smerald
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sergey Korshunov
- L. D. Landau Institute for Theoretical Physics, Kosygina 2, Moscow 119334, Russia
| | - Frédéric Mila
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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24
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Darie C, Lepoittevin C, Klein H, Kodjikian S, Bordet P, Colin CV, Lebedev OI, Deudon C, Payen C. A new high pressure form of Ba3NiSb2O9. J SOLID STATE CHEM 2016. [DOI: 10.1016/j.jssc.2016.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Smerald A, Mila F. Disorder-Driven Spin-Orbital Liquid Behavior in the Ba3XSb2O9 Materials. PHYSICAL REVIEW LETTERS 2015; 115:147202. [PMID: 26551821 DOI: 10.1103/physrevlett.115.147202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 06/05/2023]
Abstract
Recent experiments on the Ba(3)XSb(2)O(9) family have revealed materials that potentially realize spin- and spin-orbital liquid physics. However, the lattice structure of these materials is complicated due to the presence of charged X(2+)-Sb(5+) dumbbells, with two possible orientations. To model the lattice structure, we consider a frustrated model of charged dumbbells on the triangular lattice, with long-range Coulomb interactions. We study this model using Monte Carlo simulation, and find a freezing temperature, T(frz), at which the simulated structure factor matches well to low-temperature x-ray diffraction data for Ba(3)CuSb(2)O(9). At T=T(frz) we find a complicated "branching" structure of superexchange-linked X(2+) clusters, which form a fractal pattern with fractal dimension d(f)=1.90. We show that this gives a natural explanation for the presence of orphan spins. Finally we provide a plausible mechanism by which such dumbbell disorder can promote a spin-orbital resonant state with delocalized orphan spins.
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Affiliation(s)
- Andrew Smerald
- Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Frédéric Mila
- Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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26
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Absence of Jahn-Teller transition in the hexagonal Ba3CuSb2O9 single crystal. Proc Natl Acad Sci U S A 2015; 112:9305-9. [PMID: 26170280 DOI: 10.1073/pnas.1508941112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
With decreasing temperature, liquids generally freeze into a solid state, losing entropy in the process. However, exceptions to this trend exist, such as quantum liquids, which may remain unfrozen down to absolute zero owing to strong quantum entanglement effects that stabilize a disordered state with zero entropy. Examples of such liquids include Bose-Einstein condensation of cold atoms, superconductivity, quantum Hall state of electron systems, and quantum spin liquid state in the frustrated magnets. Moreover, recent studies have clarified the possibility of another exotic quantum liquid state based on the spin-orbital entanglement in FeSc2S4. To confirm this exotic ground state, experiments based on single-crystalline samples are essential. However, no such single-crystal study has been reported to date. Here, we report, to our knowledge, the first single-crystal study on the spin-orbital liquid candidate, 6H-Ba3CuSb2O9, and we have confirmed the absence of an orbital frozen state. In strongly correlated electron systems, orbital ordering usually appears at high temperatures in a process accompanied by a lattice deformation, called a static Jahn-Teller distortion. By combining synchrotron X-ray diffraction, electron spin resonance, Raman spectroscopy, and ultrasound measurements, we find that the static Jahn-Teller distortion is absent in the present material, which indicates that orbital ordering is suppressed down to the lowest temperatures measured. We discuss how such an unusual feature is realized with the help of spin degree of freedom, leading to a spin-orbital entangled quantum liquid state.
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27
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The crystallography of correlated disorder. Nature 2015; 521:303-9. [DOI: 10.1038/nature14453] [Citation(s) in RCA: 208] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 03/13/2015] [Indexed: 12/24/2022]
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28
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Effect of divalent Ba cation substitution with Sr on coupled 'multiglass' state in the magnetoelectric multiferroic compound Ba3NbFe3Si2O14. Sci Rep 2015; 5:9751. [PMID: 25988657 PMCID: PMC4437043 DOI: 10.1038/srep09751] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/10/2015] [Indexed: 12/01/2022] Open
Abstract
(Ba/Sr)3NbFe3Si2O14 is a magneto-electric
multiferroic with an incommensurate antiferromagnetic spiral magnetic structure
which induces electric polarization at 26 K. Structural studies show that
both the compounds have similar crystal structure down to 6 K. They
exhibit a transition, TN at 26 K and 25 K
respectively, as indicated by heat capacity and magnetization, into an
antiferromagnetic state. Although Ba and Sr are isovalent, they exhibit very
different static and dynamic magnetic behaviors. The Ba-compound exhibits a glassy
behavior with critical slowing dynamics with a freezing temperature of
~35 K and a critical exponent of 3.9, a value close to the 3-D Ising
model above TN, in addition to the invariant transition into an
antiferromagnetic state. The Sr-compound however does not exhibit any dispersive
behavior except for the invariant transition at TN. The dielectric
constant reflects magnetic behavior of the two compounds: the Ba-compound has two
distinct dispersive peaks while the Sr-compound has a single dispersive peak. Thus
the compounds exhibit coupled ‘multiglass’ behavior. The
difference in magnetic properties between the two compounds is found to be due to
modifications to super exchange path angle and length as well as anti-site defects
which stabilize either ferromagnetic or antiferromagnetic interactions.
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29
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Wang XX, Cheng XY, Lin Y, Ma C, Ruan KQ, Li XG. Multiferroic properties of hexagonal Ba3Ti2MnO9. RSC Adv 2015. [DOI: 10.1039/c5ra18392h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Noncentrosymmetric hexagonal Ba3Ti2MnO9 presents multiferroic behavior.
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Affiliation(s)
- X. X. Wang
- Key Laboratory of Strongly-Coupled Quantum Matter Physics
- Chinese Academy of Sciences
- School of Physical Sciences
- University of Science and Technology of China
- Hefei
| | - X. Y. Cheng
- Key Laboratory of Strongly-Coupled Quantum Matter Physics
- Chinese Academy of Sciences
- School of Physical Sciences
- University of Science and Technology of China
- Hefei
| | - Y. Lin
- Hefei National Laboratory for Physical Sciences at Microscale
- University of Science and Technology of China
- Hefei
- China
| | - C. Ma
- Hefei National Laboratory for Physical Sciences at Microscale
- University of Science and Technology of China
- Hefei
- China
| | - K. Q. Ruan
- Key Laboratory of Strongly-Coupled Quantum Matter Physics
- Chinese Academy of Sciences
- School of Physical Sciences
- University of Science and Technology of China
- Hefei
| | - X. G. Li
- Hefei National Laboratory for Physical Sciences at Microscale
- University of Science and Technology of China
- Hefei
- China
- School of Physics and Materials Science
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30
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Sow C, Anil Kumar PS. Evolution of ferromagnetism from a frustrated state in LixNi(2-x)O2 (0.67 < x < 0.98). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:496001. [PMID: 24184916 DOI: 10.1088/0953-8984/25/49/496001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Two-dimensional triangular-lattice antiferromagnetic systems continue to be an interesting area in condensed matter physics and LiNiO2 is one such among them. Here we present a detailed experimental magnetic study of the quasi-stoichiometric LixNi2-xO2 system (0.67 < x < 0.98). It exhibits a variety of magnetic ground states-namely spin glass, cluster glass, re-entrant spin glass and ferromagnetic. This study deals with the magnetic properties of these four distinct ground states. The spin glass state is evidenced by the frequency-dependent peak shift as well as the time-dependent slow dynamics (magnetic relaxation, magnetic memory effect etc). By tuning the Li deficiency in a controlled manner, an increase in the ordering temperature is observed. Most strikingly, with the Li deficiency the nature of the magnetic ground state is changed from spin glass to ferromagnetic, with two intermediate states-namely cluster glass and re-entrant spin glass. The critical behaviour of the re-entrant spin glass is also studied here. The critical exponents (β, γ and δ) are extracted from the modified Arrot plot, Kouvel-Fisher method, and critical isotherm analysis. The critical exponents match with the long-range mean-field model. The values of the critical exponents are confirmed by the Widom scaling law: δ = 1 + γβ(-1). Furthermore, the universality class of the scaling relations is verified, where the scaled m and scaled h collapse into two branches. Finally, based on our observations, a phase diagram is constructed.
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Affiliation(s)
- Chanchal Sow
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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Paddison JAM, Stewart JR, Manuel P, Courtois P, McIntyre GJ, Rainford BD, Goodwin AL. Emergent frustration in co-doped β-Mn. PHYSICAL REVIEW LETTERS 2013; 110:267207. [PMID: 23848920 DOI: 10.1103/physrevlett.110.267207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/26/2013] [Indexed: 06/02/2023]
Abstract
We investigate low-temperature spin correlations in the metallic frustrated magnet β-Mn1-xCox. Single-crystal polarized-neutron scattering experiments reveal the persistence of highly structured magnetic diffuse scattering and the absence of periodic magnetic order to T=0.05 K. We employ reverse Monte Carlo refinements and mean-field theory calculations to construct an effective Hamiltonian which accounts for the magnetic scattering. The interactions we identify describe an emergent spin structure which mimics the triangular lattice antiferromagnet, one of the canonical models of frustrated magnetism.
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Affiliation(s)
- Joseph A M Paddison
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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Ishiguro Y, Kimura K, Nakatsuji S, Tsutsui S, Baron AQR, Kimura T, Wakabayashi Y. Dynamical spin–orbital correlation in the frustrated magnet Ba3CuSb2O9. Nat Commun 2013; 4:2022. [PMID: 23771213 DOI: 10.1038/ncomms3022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/17/2013] [Indexed: 11/09/2022] Open
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Brzezicki W, Dziarmaga J, Oleś AM. Noncollinear magnetic order stabilized by entangled spin-orbital fluctuations. PHYSICAL REVIEW LETTERS 2012; 109:237201. [PMID: 23368254 DOI: 10.1103/physrevlett.109.237201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Indexed: 06/01/2023]
Abstract
Quantum phase transitions in the two-dimensional Kugel-Khomskii model on a square lattice are studied using the plaquette mean field theory and the entanglement renormalization Ansatz. When 3z(2)-r(2) orbitals are favored by the crystal field and Hund's exchange is finite, both methods give a noncollinear exotic magnetic order that consists of four sublattices with mutually orthogonal nearest-neighbor and antiferromagnetic second-neighbor spins. We derive an effective frustrated spin model with second- and third-neighbor spin interactions which stabilize this phase and follow from spin-orbital quantum fluctuations involving spin singlets entangled with orbital excitations.
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Affiliation(s)
- Wojciech Brzezicki
- Marian Smoluchowski Institute of Physics, Jagellonian University, Reymonta 4, PL-30059 Kraków, Poland
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Quilliam JA, Bert F, Kermarrec E, Payen C, Guillot-Deudon C, Bonville P, Baines C, Luetkens H, Mendels P. Singlet ground state of the quantum antiferromagnet Ba(3)CuSb(2)O(9). PHYSICAL REVIEW LETTERS 2012; 109:117203. [PMID: 23005669 DOI: 10.1103/physrevlett.109.117203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Indexed: 06/01/2023]
Abstract
We present local probe results on the honeycomb lattice antiferromagnet Ba(3)CuSb(2)O(9). Muon spin relaxation measurements in a zero field down to 20 mK show unequivocally that there is a total absence of spin freezing in the ground state. Sb NMR measurements allow us to track the intrinsic susceptibility of the lattice, which shows a maximum at around 55 K and drops to zero in the low-temperature limit. The spin-lattice relaxation rate shows two characteristic energy scales, including a field-dependent crossover to exponential low-temperature behavior, implying gapped magnetic excitations.
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Affiliation(s)
- J A Quilliam
- Laboratoire de Physique des Solides, Université Paris-Sud 11, UMR CNRS 8502, 91405 Orsay, France
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Abstract
The frustrated ordering of dipoles created by copper and antimony ions in an oxide material may help to create an exotic quantum electronic state.
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Affiliation(s)
- Leon Balents
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, CA 93106, USA.
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