1
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Fumega AO, Lado JL. Nature of the Unconventional Heavy-Fermion Kondo State in Monolayer CeSiI. NANO LETTERS 2024; 24:4272-4278. [PMID: 38394370 PMCID: PMC11010227 DOI: 10.1021/acs.nanolett.4c00619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024]
Abstract
CeSiI has been recently isolated in the ultrathin limit, establishing CeSiI as the first intrinsic two-dimensional van der Waals heavy-fermion material up to 85 K. We show that, due to the strong spin-orbit coupling, the local moments develop a multipolar real-space magnetic texture, leading to local pseudospins with a nearly vanishing net moment. To elucidate its Kondo-screened regime, we extract from first-principles the parameters of the Kondo lattice model describing this material. We develop a pseudofermion methodology in combination with ab initio calculations to reveal the nature of the heavy-fermion state in CeSiI. We analyze the competing magnetic interactions leading to an unconventional heavy-fermion order as a function of the magnetic exchange between the localized f-electrons and the strength of the Kondo coupling. Our results show that the magnetic exchange interactions promote an unconventional momentum-dependent Kondo-screened phase, establishing the nature of the heavy-fermion state observed in CeSiI.
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Affiliation(s)
- Adolfo O. Fumega
- Department of Applied
Physics, Aalto University, 02150 Espoo, Finland
| | - Jose L. Lado
- Department of Applied
Physics, Aalto University, 02150 Espoo, Finland
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2
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Zhang X, Carbin T, Culver AB, Du K, Wang K, Cheong SW, Roy R, Kogar A. Light-induced electronic polarization in antiferromagnetic Cr 2O 3. NATURE MATERIALS 2024:10.1038/s41563-024-01852-w. [PMID: 38561519 DOI: 10.1038/s41563-024-01852-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
In a solid, the electronic subsystem can exhibit incipient order with lower point group symmetry than the crystal lattice. Ultrafast external fields that couple exclusively to electronic order parameters have rarely been investigated, however, despite their potential importance in inducing exotic effects. Here we show that when inversion symmetry is broken by the antiferromagnetic order in Cr2O3, transmitting a linearly polarized light pulse through the crystal gives rise to an in-plane rotational symmetry-breaking (from C3 to C1) via optical rectification. Using interferometric time-resolved second harmonic generation, we show that the ultrafast timescale of the symmetry reduction is indicative of a purely electronic response; the underlying spin and crystal structures remain unaffected. The symmetry-broken state exhibits a dipole moment, and its polar axis can be controlled with the incident light. Our results establish a coherent nonlinear optical protocol by which to break electronic symmetries and produce unconventional electronic effects in solids.
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Affiliation(s)
- Xinshu Zhang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Tyler Carbin
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Adrian B Culver
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
- Mani L. Bhaumik Institute for Theoretical Physics, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Kai Du
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Kefeng Wang
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ, USA
| | - Rahul Roy
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
- Mani L. Bhaumik Institute for Theoretical Physics, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA
| | - Anshul Kogar
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA, USA.
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3
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Mandal M, Drucker NC, Siriviboon P, Nguyen T, Boonkird A, Lamichhane TN, Okabe R, Chotrattanapituk A, Li M. Topological Superconductors from a Materials Perspective. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:6184-6200. [PMID: 37637011 PMCID: PMC10448998 DOI: 10.1021/acs.chemmater.3c00713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/12/2023] [Indexed: 08/29/2023]
Abstract
Topological superconductors (TSCs) have garnered significant research and industry attention in the past two decades. By hosting Majorana bound states which can be used as qubits that are robust against local perturbations, TSCs offer a promising platform toward (nonuniversal) topological quantum computation. However, there has been a scarcity of TSC candidates, and the experimental signatures that identify a TSC are often elusive. In this Perspective, after a short review of the TSC basics and theories, we provide an overview of the TSC materials candidates, including natural compounds and synthetic material systems. We further introduce various experimental techniques to probe TSCs, focusing on how a system is identified as a TSC candidate and why a conclusive answer is often challenging to draw. We conclude by calling for new experimental signatures and stronger computational support to accelerate the search for new TSC candidates.
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Affiliation(s)
- Manasi Mandal
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139, United States
| | - Nathan C. Drucker
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- School
of Engineering and Applied Sciences, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Phum Siriviboon
- Department
of Physics, MIT, Cambridge, Massachusetts 02139, United States
| | - Thanh Nguyen
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139, United States
| | - Artittaya Boonkird
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139, United States
| | - Tej Nath Lamichhane
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139, United States
| | - Ryotaro Okabe
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Chemistry, MIT, Cambridge, Massachusetts 02139, United States
| | - Abhijatmedhi Chotrattanapituk
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Electrical Engineering and Computer Science, MIT, Cambridge, Massachusetts 02139, United States
| | - Mingda Li
- Quantum
Measurement Group, MIT, Cambridge, Massachusetts 02139, United States
- Department
of Nuclear Science and Engineering, MIT, Cambridge, Massachusetts 02139, United States
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4
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Herrera E, Guillamón I, Barrena V, Herrera WJ, Galvis JA, Yeyati AL, Rusz J, Oppeneer PM, Knebel G, Brison JP, Flouquet J, Aoki D, Suderow H. Quantum-well states at the surface of a heavy-fermion superconductor. Nature 2023; 616:465-469. [PMID: 36949204 PMCID: PMC10115632 DOI: 10.1038/s41586-023-05830-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 02/13/2023] [Indexed: 03/24/2023]
Abstract
Two-dimensional electronic states at surfaces are often observed in simple wide-band metals such as Cu or Ag (refs. 1-4). Confinement by closed geometries at the nanometre scale, such as surface terraces, leads to quantized energy levels formed from the surface band, in stark contrast to the continuous energy dependence of bulk electron bands2,5-10. Their energy-level separation is typically hundreds of meV (refs. 3,6,11). In a distinct class of materials, strong electronic correlations lead to so-called heavy fermions with a strongly reduced bandwidth and exotic bulk ground states12,13. Quantum-well states in two-dimensional heavy fermions (2DHFs) remain, however, notoriously difficult to observe because of their tiny energy separation. Here we use millikelvin scanning tunnelling microscopy (STM) to study atomically flat terraces on U-terminated surfaces of the heavy-fermion superconductor URu2Si2, which exhibits a mysterious hidden-order (HO) state below 17.5 K (ref. 14). We observe 2DHFs made of 5f electrons with an effective mass 17 times the free electron mass. The 2DHFs form quantized states separated by a fraction of a meV and their level width is set by the interaction with correlated bulk states. Edge states on steps between terraces appear along one of the two in-plane directions, suggesting electronic symmetry breaking at the surface. Our results propose a new route to realize quantum-well states in strongly correlated quantum materials and to explore how these connect to the electronic environment.
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Affiliation(s)
- Edwin Herrera
- Facultad de Ingeniería y Ciencias Básicas, Universidad Central, Bogotá, Colombia.
- Departamento de Física, Universidad Nacional de Colombia, Bogotá, Colombia.
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada UAM/CSIC, Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain.
| | - Isabel Guillamón
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada UAM/CSIC, Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Víctor Barrena
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada UAM/CSIC, Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - William J Herrera
- Departamento de Física, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Jose Augusto Galvis
- Facultad de Ingeniería y Ciencias Básicas, Universidad Central, Bogotá, Colombia
- School of Engineering, Science and Technology, Universidad del Rosario, Bogotá, Colombia
| | - Alfredo Levy Yeyati
- Departamento de Física Teórica de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Ján Rusz
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Georg Knebel
- University Grenoble Alpes, CEA, Grenoble-INP, IRIG, PHELIQS, Grenoble, France
| | - Jean Pascal Brison
- University Grenoble Alpes, CEA, Grenoble-INP, IRIG, PHELIQS, Grenoble, France
| | - Jacques Flouquet
- University Grenoble Alpes, CEA, Grenoble-INP, IRIG, PHELIQS, Grenoble, France
| | - Dai Aoki
- Institute for Materials Research (IMR), Tohoku University, Oarai, Japan
| | - Hermann Suderow
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada UAM/CSIC, Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain.
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5
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Qiu WX, Zou JY, Luo AY, Cui ZH, Song ZD, Gao JH, Wang YL, Xu G. Efficient Method for Prediction of Metastable or Ground Multipolar Ordered States and Its Application in Monolayer α-RuX_{3} (X=Cl, I). PHYSICAL REVIEW LETTERS 2021; 127:147202. [PMID: 34652212 DOI: 10.1103/physrevlett.127.147202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 07/26/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Exotic high-rank multipolar order parameters have been found to be unexpectedly active in more and more correlated materials in recent years. Such multipoles are usually dubbed "hidden orders" since they are insensitive to common experimental probes. Theoretically, it is also difficult to predict multipolar orders via ab initio calculations in real materials. Here, we present an efficient method to predict possible multipoles in materials based on linear response theory under random phase approximation. Using this method, we successfully predict two pure metastable magnetic octupolar states in monolayer α-RuCl_{3}, which is confirmed by self-consistent unrestricted Hartree-Fock calculations. We then demonstrate that these octupolar states can be stabilized in monolayer α-RuI_{3}, one of which becomes the octupolar ground state. Furthermore, we also predict a fingerprint of an orthogonal magnetization pattern produced by the octupole moment that can be easily detected by experiment. The method and the example presented in this Letter serve as a guide for searching multipolar order parameters in other correlated materials.
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Affiliation(s)
- Wen-Xuan Qiu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jin-Yu Zou
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ai-Yun Luo
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhi-Hai Cui
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhi-Da Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Jin-Hua Gao
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yi-Lin Wang
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Xu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
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6
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Kim JH, Peets DC, Reehuis M, Adler P, Maljuk A, Ritschel T, Allison MC, Geck J, Mardegan JRL, Bereciartua Perez PJ, Francoual S, Walters AC, Keller T, Abdala PM, Pattison P, Dosanjh P, Keimer B. Hidden Charge Order in an Iron Oxide Square-Lattice Compound. PHYSICAL REVIEW LETTERS 2021; 127:097203. [PMID: 34506205 DOI: 10.1103/physrevlett.127.097203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Since the discovery of charge disproportionation in the FeO_{2} square-lattice compound Sr_{3}Fe_{2}O_{7} by Mössbauer spectroscopy more than fifty years ago, the spatial ordering pattern of the disproportionated charges has remained "hidden" to conventional diffraction probes, despite numerous x-ray and neutron scattering studies. We have used neutron Larmor diffraction and Fe K-edge resonant x-ray scattering to demonstrate checkerboard charge order in the FeO_{2} planes that vanishes at a sharp second-order phase transition upon heating above 332 K. Stacking disorder of the checkerboard pattern due to frustrated interlayer interactions broadens the corresponding superstructure reflections and greatly reduces their amplitude, thus explaining the difficulty of detecting them by conventional probes. We discuss the implications of these findings for research on "hidden order" in other materials.
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Affiliation(s)
- Jung-Hwa Kim
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
| | - Darren C Peets
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
- Ningbo Institute for Materials Technology and Engineering, Chinese Academy of Sciences, Zhenhai, Ningbo, 315201 Zhejiang, China
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Manfred Reehuis
- Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - Peter Adler
- Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany
| | - Andrey Maljuk
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
- Leibniz Institut für Festkörper- und Werkstoffforschung, D-01171 Dresden, Germany
| | - Tobias Ritschel
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Morgan C Allison
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Jochen Geck
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01069 Dresden, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | | | | | - Sonia Francoual
- Deutsches Elektronen-Synchrotron DESY, Hamburg 22603, Germany
| | - Andrew C Walters
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Thomas Keller
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Heinz Maier-Leibnitz Zentrum (MLZ), D-85748 Garching, Germany
| | | | - Philip Pattison
- SNBL at ESRF, BP 220, F-38042 Grenoble Cedex 9, France
- Laboratory for Quantum Magnetism, École polytechnique fédérale de Lausanne (EPFL), BSP-Dorigny, CH-1015 Lausanne, Switzerland
| | - Pinder Dosanjh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 Canada
| | - Bernhard Keimer
- Max-Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany
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7
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High-pressure phase diagrams of FeSe 1-xTe x: correlation between suppressed nematicity and enhanced superconductivity. Nat Commun 2021; 12:381. [PMID: 33452257 PMCID: PMC7810696 DOI: 10.1038/s41467-020-20621-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/13/2020] [Indexed: 11/23/2022] Open
Abstract
The interplay among magnetism, electronic nematicity, and superconductivity is the key issue in strongly correlated materials including iron-based, cuprate, and heavy-fermion superconductors. Magnetic fluctuations have been widely discussed as a pairing mechanism of unconventional superconductivity, but recent theory predicts that quantum fluctuations of nematic order may also promote high-temperature superconductivity. This has been studied in FeSe1−xSx superconductors exhibiting nonmagnetic nematic and pressure-induced antiferromagnetic orders, but its abrupt suppression of superconductivity at the nematic end point leaves the nematic-fluctuation driven superconductivity unconfirmed. Here we report on systematic studies of high-pressure phase diagrams up to 8 GPa in high-quality single crystals of FeSe1−xTex. When Te composition x(Te) becomes larger than 0.1, the high-pressure magnetic order disappears, whereas the pressure-induced superconducting dome near the nematic end point is continuously found up to x(Te) ≈ 0.5. In contrast to FeSe1−xSx, enhanced superconductivity in FeSe1−xTex does not correlate with magnetism but with the suppression of nematicity, highlighting the paramount role of nonmagnetic nematic fluctuations for high-temperature superconductivity in this system. Despite studies in FeSe1−xSx, it is yet unconfirmed whether nematic fluctuation can induce superconductivity. Here, the authors study single crystals of FeSe1−xTex showing enhanced superconductivity upon suppression of nematicity.
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8
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Fu X, Huang Y, Shi Q, Shklovskii BI, Zudov MA, Gardner GC, Manfra MJ. Hidden Quantum Hall Stripes in Al_{x}Ga_{1-x}As/Al_{0.24}Ga_{0.76}As Quantum Wells. PHYSICAL REVIEW LETTERS 2020; 125:236803. [PMID: 33337202 DOI: 10.1103/physrevlett.125.236803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 10/30/2020] [Indexed: 06/12/2023]
Abstract
We report on transport signatures of hidden quantum Hall stripe (hQHS) phases in high (N>2) half-filled Landau levels of Al_{x}Ga_{1-x}As/Al_{0.24}Ga_{0.76}As quantum wells with varying Al mole fraction x<10^{-3}. Residing between the conventional stripe phases (lower N) and the isotropic liquid phases (higher N), where resistivity decreases as 1/N, these hQHS phases exhibit isotropic and N-independent resistivity. Using the experimental phase diagram, we establish that the stripe phases are more robust than theoretically predicted, calling for improved theoretical treatment. We also show that, unlike conventional stripe phases, the hQHS phases do not occur in ultrahigh mobility GaAs quantum wells but are likely to be found in other systems.
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Affiliation(s)
- X Fu
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Yi Huang
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Q Shi
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - B I Shklovskii
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - M A Zudov
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - G C Gardner
- Microsoft Quantum Lab Purdue, Purdue University, West Lafayette, Indiana 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - M J Manfra
- Microsoft Quantum Lab Purdue, Purdue University, West Lafayette, Indiana 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
- School of Electrical and Computer Engineering and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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9
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Le T, Sun Y, Jin HK, Che L, Yin L, Li J, Pang G, Xu C, Zhao L, Kittaka S, Sakakibara T, Machida K, Sankar R, Yuan H, Chen G, Xu X, Li S, Zhou Y, Lu X. Evidence for nematic superconductivity of topological surface states in PbTaSe 2. Sci Bull (Beijing) 2020; 65:1349-1355. [PMID: 36659213 DOI: 10.1016/j.scib.2020.04.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/27/2020] [Accepted: 04/23/2020] [Indexed: 01/21/2023]
Abstract
Spontaneous symmetry breaking has been a paradigm to describe the phase transitions in condensed matter physics. In addition to the continuous electromagnetic gauge symmetry, an unconventional superconductor can break discrete symmetries simultaneously, such as time reversal and lattice rotational symmetry. In this work we report a characteristic in-plane 2-fold behaviour of the resistive upper critical field and point-contact spectra on the superconducting semimetal PbTaSe2 with topological nodal-rings, despite its hexagonal lattice symmetry (or D3h in bulk while C3v on surface, to be precise). The 2-fold behaviour persists up to its surface upper critical field Hc2R even though bulk superconductivity has been suppressed at its bulk upper critical field Hc2HC≪Hc2R, signaling its probable surface-only electronic nematicity. In addition, we do not observe any lattice rotational symmetry breaking signal from field-angle-dependent specific heat within the resolution. It is worth noting that such surface-only electronic nematicity is in sharp contrast to the observation in the topological superconductor candidate, CuxBi2Se3, where the nematicity occurs in various bulk measurements. In combination with theory, superconducting nematicity is likely to emerge from the topological surface states of PbTaSe2, rather than the proximity effect. The issue of time reversal symmetry breaking is also addressed. Thus, our results on PbTaSe2 shed new light on possible routes to realize nematic superconductivity with nontrivial topology.
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Affiliation(s)
- Tian Le
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Yue Sun
- Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 252-5258, Japan.
| | - Hui-Ke Jin
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Liqiang Che
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Lichang Yin
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Jie Li
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Guiming Pang
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China
| | - Chunqiang Xu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Lingxiao Zhao
- Beijing National Laboratory for Condensed Matter Physics & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shunichiro Kittaka
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Toshiro Sakakibara
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Kazushige Machida
- Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Raman Sankar
- Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan, China
| | - Huiqiu Yuan
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310027, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Genfu Chen
- Beijing National Laboratory for Condensed Matter Physics & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Xiaofeng Xu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China.
| | - Shiyan Li
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yi Zhou
- Beijing National Laboratory for Condensed Matter Physics & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xin Lu
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory of Quantum Technology and Device, Zhejiang University, Hangzhou 310027, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
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10
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Wang L, He M, Hardy F, Aoki D, Willa K, Flouquet J, Meingast C. Electronic Nematicity in URu_{2}Si_{2} Revisited. PHYSICAL REVIEW LETTERS 2020; 124:257601. [PMID: 32639769 DOI: 10.1103/physrevlett.124.257601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
The nature of the hidden-order (HO) state in URu_{2}Si_{2} remains one of the major unsolved issues in heavy-fermion physics. Recently, torque magnetometry, x-ray diffraction, and elastoresistivity data have suggested that the HO phase transition at T_{HO}≈ 17.5 K is driven by electronic nematic effects. Here, we search for thermodynamic signatures of this purported structural instability using anisotropic thermal expansion, Young's modulus, elastoresistivity, and specific-heat measurements. In contrast to the published results, we find no evidence of a rotational symmetry breaking in any of our data. Interestingly, our elastoresistivity measurements, which are in full agreement with published results, exhibit a Curie-Weiss divergence, which we however attribute to a volume and not to a symmetry-breaking effect. Finally, clear evidence for thermal fluctuations is observed in our heat-capacity data, from which we estimate the HO correlation length.
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Affiliation(s)
- Liran Wang
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Mingquan He
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Frédéric Hardy
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Dai Aoki
- Université Grenoble Alpes, CEA, PHELIQS, 38000 Grenoble, France
- Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313, Japan
| | - Kristin Willa
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | | | - Christoph Meingast
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
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11
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Mydosh JA, Oppeneer PM, Riseborough PS. Hidden order and beyond: an experimental-theoretical overview of the multifaceted behavior of URu 2Si 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:143002. [PMID: 31801118 DOI: 10.1088/1361-648x/ab5eba] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This topical review describes the multitude of unconventional behaviors in the hidden order, heavy fermion, antiferromagnetic and superconducting phases of the intermetallic compound URu2Si2 when tuned with pressure, magnetic field, and substitutions for all three elements. Such 'perturbations' result in a variety of new phases beyond the mysterious hidden order that are only now being slowly understood through a series of state-of-the-science experimentation, along with an array of novel theoretical approaches. Despite all these efforts spanning more than 30 years, hidden order (HO) remains puzzling and non-clarified, and the search continues in 2019 into a fourth decade for its final resolution. Here we attempt to update the present situation of URu2Si2 importing the latest experimental results and theoretical proposals. First, let us consider the pristine compound as a function of temperature and report the recent measurements and models relating to its heavy Fermi liquid crossover, its HO and superconductivity (SC). Recent experiments and theories are surmized that address four-fold symmetry breaking (or nematicity), Isingness and unconventional excitation modes. Second, we review the pressure dependence of URu2Si2 and its transformation to antiferromagnetic long-range order. Next we confront the dramatic high magnetic-field phases requiring fields above 40 T. And finally, we attempt to answer how does random substitutions of other 5f elements for U, and 3d, 4d, and 5d elements for Ru, and even P for Si affect and transform the HO. Commensurately, recent theoretical models are summarized and then related to the intriguing experimental behavior.
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Affiliation(s)
- J A Mydosh
- Institute Lorentz and Kamerlingh Onnes Laboratory, Leiden University, NL-2300 RA Leiden, The Netherlands
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12
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Novel electronic nematicity in heavily hole-doped iron pnictide superconductors. Proc Natl Acad Sci U S A 2020; 117:6424-6429. [PMID: 32165540 DOI: 10.1073/pnas.1909172117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electronic nematicity, a correlated state that spontaneously breaks rotational symmetry, is observed in several layered quantum materials. In contrast to their liquid-crystal counterparts, the nematic director cannot usually point in an arbitrary direction (XY nematics), but is locked by the crystal to discrete directions (Ising nematics), resulting in strongly anisotropic fluctuations above the transition. Here, we report on the observation of nearly isotropic XY-nematic fluctuations, via elastoresistance measurements, in hole-doped Ba1-x Rb x Fe2As2 iron-based superconductors. While for [Formula: see text], the nematic director points along the in-plane diagonals of the tetragonal lattice, for [Formula: see text], it points along the horizontal and vertical axes. Remarkably, for intermediate doping, the susceptibilities of these two symmetry-irreducible nematic channels display comparable Curie-Weiss behavior, thus revealing a nearly XY-nematic state. This opens a route to assess this elusive electronic quantum liquid-crystalline state.
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13
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Ghosh S, Matty M, Baumbach R, Bauer ED, Modic KA, Shekhter A, Mydosh JA, Kim EA, Ramshaw BJ. One-component order parameter in URu 2Si 2 uncovered by resonant ultrasound spectroscopy and machine learning. SCIENCE ADVANCES 2020; 6:eaaz4074. [PMID: 32181367 PMCID: PMC7060057 DOI: 10.1126/sciadv.aaz4074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
The unusual correlated state that emerges in URu2Si2 below T HO = 17.5 K is known as "hidden order" because even basic characteristics of the order parameter, such as its dimensionality (whether it has one component or two), are "hidden." We use resonant ultrasound spectroscopy to measure the symmetry-resolved elastic anomalies across T HO. We observe no anomalies in the shear elastic moduli, providing strong thermodynamic evidence for a one-component order parameter. We develop a machine learning framework that reaches this conclusion directly from the raw data, even in a crystal that is too small for traditional resonant ultrasound. Our result rules out a broad class of theories of hidden order based on two-component order parameters, and constrains the nature of the fluctuations from which unconventional superconductivity emerges at lower temperature. Our machine learning framework is a powerful new tool for classifying the ubiquitous competing orders in correlated electron systems.
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Affiliation(s)
- Sayak Ghosh
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA
| | - Michael Matty
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA
| | - Ryan Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Eric D. Bauer
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - K. A. Modic
- Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Arkady Shekhter
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - J. A. Mydosh
- Kamerlingh Onnes Laboratory and Institute Lorentz, Leiden University, 2300RA Leiden, Netherlands
| | - Eun-Ah Kim
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA
| | - B. J. Ramshaw
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA
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14
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Song Y, Yuan D, Lu X, Xu Z, Bourret-Courchesne E, Birgeneau RJ. Strain-Induced Spin-Nematic State and Nematic Susceptibility Arising from 2×2 Fe Clusters in KFe_{0.8}Ag_{1.2}Te_{2}. PHYSICAL REVIEW LETTERS 2019; 123:247205. [PMID: 31922861 DOI: 10.1103/physrevlett.123.247205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Spin nematics break spin-rotational symmetry while maintaining time-reversal symmetry, analogous to liquid crystal nematics that break spatial rotational symmetry while maintaining translational symmetry. Although several candidate spin nematics have been proposed, the identification and characterization of such a state remain challenging because the spin-nematic order parameter does not couple directly to experimental probes. KFe_{0.8}Ag_{1.2}Te_{2} (K_{5}Fe_{4}Ag_{6}Te_{10}, KFAT) is a local-moment magnet consisting of well-separated 2×2 Fe clusters, and in its ground state the clusters order magnetically, breaking both spin-rotational and time-reversal symmetries. Using uniform magnetic susceptibility and neutron scattering measurements, we find a small strain induces sizable spin anisotropy in the paramagnetic state of KFAT, manifestly breaking spin-rotational symmetry while retaining time-reversal symmetry, resulting in a strain-induced spin-nematic state in which the 2×2 clusters act as the spin analog of molecules in a liquid crystal nematic. The strain-induced spin anisotropy in KFAT allows us to probe its nematic susceptibility, revealing a divergentlike increase upon cooling, indicating the ordered ground state is driven by a spin-orbital entangled nematic order parameter.
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Affiliation(s)
- Yu Song
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Dongsheng Yuan
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Xingye Lu
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Zhijun Xu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg Maryland 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - Edith Bourret-Courchesne
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Robert J Birgeneau
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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15
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Unveiling hidden multipolar orders with magnetostriction. Nat Commun 2019; 10:4092. [PMID: 31501429 PMCID: PMC6733943 DOI: 10.1038/s41467-019-11913-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/12/2019] [Indexed: 11/28/2022] Open
Abstract
Broken symmetries in solids involving higher order multipolar degrees of freedom are historically referred to as “hidden orders” due to the formidable task of detecting them with conventional probes. In this work, we theoretically propose that magnetostriction provides a powerful and novel tool to directly detect higher-order multipolar symmetry breaking—such as the elusive octupolar order—by examining scaling behaviour of length change with respect to an applied magnetic field h. Employing a symmetry-based Landau theory, we focus on the family of Pr-based cage compounds with strongly correlated f-electrons, Pr(Ti,V,Ir)2(Al,Zn)20, whose low energy degrees of freedom are purely higher-order multipoles: quadrupoles \documentclass[12pt]{minimal}
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\begin{document}$${\cal{O}}_{20,22}$$\end{document}O20,22 and octupole \documentclass[12pt]{minimal}
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\begin{document}$${\cal{T}}_{xyz}$$\end{document}Txyz. We demonstrate that a magnetic field along the [111] direction induces a distinct linear-in-h length change below the octupolar ordering temperature. The resulting “magnetostriction coefficient” is directly proportional to the octupolar order parameter, thus providing clear access to such subtle order parameters. Higher-order multipolar phases are unusual states that can form in correlated materials and are difficult to observe as they do not directly couple to conventional probes. Patri et al. theoretically show that angle-dependent magnetostriction measurements can probe quadrupolar and octupolar ordering.
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16
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Murayama H, Sato Y, Kurihara R, Kasahara S, Mizukami Y, Kasahara Y, Uchiyama H, Yamamoto A, Moon EG, Cai J, Freyermuth J, Greven M, Shibauchi T, Matsuda Y. Diagonal nematicity in the pseudogap phase of HgBa 2CuO 4+δ. Nat Commun 2019; 10:3282. [PMID: 31337758 PMCID: PMC6650423 DOI: 10.1038/s41467-019-11200-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/27/2019] [Indexed: 11/09/2022] Open
Abstract
The pseudogap phenomenon in the cuprates is arguably the most mysterious puzzle in the field of high-temperature superconductivity. The tetragonal cuprate HgBa2CuO4+δ, with only one CuO2 layer per primitive cell, is an ideal system to tackle this puzzle. Here, we measure the magnetic susceptibility anisotropy within the CuO2 plane with exceptionally high-precision magnetic torque experiments. Our key finding is that a distinct two-fold in-plane anisotropy sets in below the pseudogap temperature T*, which provides thermodynamic evidence for a nematic phase transition with broken four-fold symmetry. Surprisingly, the nematic director orients along the diagonal direction of the CuO2 square lattice, in sharp contrast to the bond nematicity along the Cu-O-Cu direction. Another remarkable feature is that the enhancement of the diagonal nematicity with decreasing temperature is suppressed around the temperature at which short-range charge-density-wave formation occurs. Our result suggests a competing relationship between diagonal nematic and charge-density-wave order in HgBa2CuO4+δ.
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Affiliation(s)
- H Murayama
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Sato
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - R Kurihara
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - S Kasahara
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Mizukami
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - H Uchiyama
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan.,Research and Utilization Division, Japan Synchrotron Radiation Research Institute (SPring-8/JASRI), 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan
| | - A Yamamoto
- Graduate School of Engineering and Science, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo, 135-8584, Japan
| | - E-G Moon
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea
| | - J Cai
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.,Physics Department, University of Maryland, College Park, MD, 20742-4111, USA
| | - J Freyermuth
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.,Department of Physics, The Ohio State University, Columbus, OH, 43210-1117, USA
| | - M Greven
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
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17
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Sun Y, Kittaka S, Sakakibara T, Machida K, Wang J, Wen J, Xing X, Shi Z, Tamegai T. Quasiparticle Evidence for the Nematic State above T_{c} in Sr_{x}Bi_{2}Se_{3}. PHYSICAL REVIEW LETTERS 2019; 123:027002. [PMID: 31386520 DOI: 10.1103/physrevlett.123.027002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 06/10/2023]
Abstract
In the electronic nematic state, an electronic system has a lower symmetry than the crystal structure of the same system. Electronic nematic states have been observed in various unconventional superconductors such as cuprate, iron-based, heavy-fermion, and topological superconductors. The relation between nematicity and superconductivity is a major unsolved problem in condensed matter physics. By angle-resolved specific heat measurements, we report bulk quasiparticle evidence of nematicity in the topological superconductor Sr_{x}Bi_{2}Se_{3}. The specific heat exhibited a clear twofold symmetry despite the threefold symmetric lattice. Most importantly, the twofold symmetry appeared in the normal state above the superconducting transition temperature. This is explained by the angle-dependent Zeeman effect due to the anisotropic density of states in the nematic phase. Such results highlight the interrelation between nematicity and unconventional superconductivity.
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Affiliation(s)
- Yue Sun
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 252-5258, Japan
| | - Shunichiro Kittaka
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Toshiro Sakakibara
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Kazushige Machida
- Department of Physics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Jinghui Wang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Jinsheng Wen
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Xiangzhuo Xing
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Zhixiang Shi
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Tsuyoshi Tamegai
- Department of Applied Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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18
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Shiomi Y, Watanabe H, Masuda H, Takahashi H, Yanase Y, Ishiwata S. Observation of a Magnetopiezoelectric Effect in the Antiferromagnetic Metal EuMnBi_{2}. PHYSICAL REVIEW LETTERS 2019; 122:127207. [PMID: 30978058 DOI: 10.1103/physrevlett.122.127207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Indexed: 06/09/2023]
Abstract
We have experimentally studied a magnetopiezoelectric effect predicted recently for magnetic metals with low crystal symmetries. In EuMnBi_{2} with antiferromagnetic Mn moments at 77 K, dynamic displacements emerge along the a direction upon application of ac electric fields in the c direction and increase in proportion to the applied electric fields. Such displacements are not observed along the c direction of EuMnBi_{2} or EuZnBi_{2} with nonmagnetic Zn ions. As temperature increases from 77 K, the displacement signals decrease and disappear at about 200 K, above which electric conduction changes from coherent to incoherent. These results demonstrate the emergence of the magnetopiezoelectric effect in a magnetic metal lacking inversion and time-reversal symmetries.
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Affiliation(s)
- Y Shiomi
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Basic Science, University of Tokyo, Meguro, Tokyo 153-8902, Japan
| | - H Watanabe
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - H Masuda
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - H Takahashi
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - Y Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S Ishiwata
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
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19
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Modic KA, Bachmann MD, Ramshaw BJ, Arnold F, Shirer KR, Estry A, Betts JB, Ghimire NJ, Bauer ED, Schmidt M, Baenitz M, Svanidze E, McDonald RD, Shekhter A, Moll PJW. Resonant torsion magnetometry in anisotropic quantum materials. Nat Commun 2018; 9:3975. [PMID: 30266902 PMCID: PMC6162279 DOI: 10.1038/s41467-018-06412-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/29/2018] [Indexed: 11/09/2022] Open
Abstract
Unusual behavior in quantum materials commonly arises from their effective low-dimensional physics, reflecting the underlying anisotropy in the spin and charge degrees of freedom. Here we introduce the magnetotropic coefficient k = ∂2F/∂θ2, the second derivative of the free energy F with respect to the magnetic field orientation θ in the crystal. We show that the magnetotropic coefficient can be quantitatively determined from a shift in the resonant frequency of a commercially available atomic force microscopy cantilever under magnetic field. This detection method enables part per 100 million sensitivity and the ability to measure magnetic anisotropy in nanogram-scale samples, as demonstrated on the Weyl semimetal NbP. Measurement of the magnetotropic coefficient in the spin-liquid candidate RuCl3 highlights its sensitivity to anisotropic phase transitions and allows a quantitative comparison to other thermodynamic coefficients via the Ehrenfest relations.
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Affiliation(s)
- K A Modic
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany.
| | - Maja D Bachmann
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - B J Ramshaw
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, 14853, USA
| | - F Arnold
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - K R Shirer
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - Amelia Estry
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - J B Betts
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Nirmal J Ghimire
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.,Argonne National Laboratory, Lemont, IL, 60439, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Marcus Schmidt
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - Michael Baenitz
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | - E Svanidze
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany
| | | | - Arkady Shekhter
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Philip J W Moll
- Max-Planck-Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187, Dresden, Germany. .,EPFL STI IMX-GE MXC 240, CH-1015, Lausanne, Switzerland.
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20
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Leahy IA, Pocs CA, Siegfried PE, Graf D, Do SH, Choi KY, Normand B, Lee M. Anomalous Thermal Conductivity and Magnetic Torque Response in the Honeycomb Magnet α-RuCl_{3}. PHYSICAL REVIEW LETTERS 2017; 118:187203. [PMID: 28524686 DOI: 10.1103/physrevlett.118.187203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Indexed: 06/07/2023]
Abstract
We report on the unusual behavior of the in-plane thermal conductivity κ and torque τ response in the Kitaev-Heisenberg material α-RuCl_{3}. κ shows a striking enhancement with linear growth beyond H=7 T, where magnetic order disappears, while τ for both of the in-plane symmetry directions shows an anomaly at the same field. The temperature and field dependence of κ are far more complex than conventional phonon and magnon contributions, and require us to invoke the presence of unconventional spin excitations whose properties are characteristic of a field-induced spin-liquid phase related to the enigmatic physics of the Kitaev model in an applied magnetic field.
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Affiliation(s)
- Ian A Leahy
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Christopher A Pocs
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Peter E Siegfried
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - David Graf
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - S-H Do
- Department of Physics, Chung-Ang University, Seoul 790-784, South Korea
| | - Kwang-Yong Choi
- Department of Physics, Chung-Ang University, Seoul 790-784, South Korea
| | - B Normand
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Minhyea Lee
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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21
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Brodsky DO, Barber ME, Bruin JAN, Borzi RA, Grigera SA, Perry RS, Mackenzie AP, Hicks CW. Strain and vector magnetic field tuning of the anomalous phase in Sr 3Ru 2O 7. SCIENCE ADVANCES 2017; 3:e1501804. [PMID: 28168216 PMCID: PMC5291698 DOI: 10.1126/sciadv.1501804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
A major area of interest in condensed matter physics is the way electrons in correlated electron materials can self-organize into ordered states, and a particularly intriguing possibility is that they spontaneously choose a preferred direction of conduction. The correlated electron metal Sr3Ru2O7 has an anomalous phase at low temperatures that features strong susceptibility toward anisotropic transport. This susceptibility has been thought to indicate a spontaneous anisotropy, that is, electronic order that spontaneously breaks the point-group symmetry of the lattice, allowing weak external stimuli to select the orientation of the anisotropy. We investigate further by studying the response of Sr3Ru2O7 in the region of phase formation to two fields that lift the native tetragonal symmetry of the lattice: in-plane magnetic field and orthorhombic lattice distortion through uniaxial pressure. The response to uniaxial pressure is surprisingly strong: Compressing the lattice by ~0.1% induces an approximately 100% transport anisotropy. However, neither the in-plane field nor the pressure phase diagrams are qualitatively consistent with spontaneous symmetry reduction. Instead, both are consistent with a multicomponent order parameter that is likely to preserve the point-group symmetry of the lattice, but is highly susceptible to perturbation.
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Affiliation(s)
- Daniel O. Brodsky
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, North Haugh, University of St Andrews, St Andrews KY16 9SS, U.K
| | - Mark E. Barber
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, North Haugh, University of St Andrews, St Andrews KY16 9SS, U.K
| | - Jan A. N. Bruin
- Scottish Universities Physics Alliance, School of Physics and Astronomy, North Haugh, University of St Andrews, St Andrews KY16 9SS, U.K
- Max Planck Institute for Solid State Physics, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Rodolfo A. Borzi
- Instituto de Física de Líquidos y Sistemas Biológicos, Universidad Nacional de La Plata–Consejo Nacional de Investigaciones Científicas y Técnicas, 1900 La Plata, Argentina
| | - Santiago A. Grigera
- Scottish Universities Physics Alliance, School of Physics and Astronomy, North Haugh, University of St Andrews, St Andrews KY16 9SS, U.K
- Instituto de Física de Líquidos y Sistemas Biológicos, Universidad Nacional de La Plata–Consejo Nacional de Investigaciones Científicas y Técnicas, 1900 La Plata, Argentina
| | - Robin S. Perry
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, U.K
| | - Andrew P. Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, North Haugh, University of St Andrews, St Andrews KY16 9SS, U.K
| | - Clifford W. Hicks
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
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22
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Morr DK. Theory of scanning tunneling spectroscopy: from Kondo impurities to heavy fermion materials. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:014502. [PMID: 27823990 DOI: 10.1088/0034-4885/80/1/014502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Kondo systems ranging from the single Kondo impurity to heavy fermion materials present us with a plethora of unconventional properties whose theoretical understanding is still one of the major open problems in condensed matter physics. Over the last few years, groundbreaking scanning tunneling spectroscopy (STS) experiments have provided unprecedented new insight into the electronic structure of Kondo systems. Interpreting the results of these experiments-the differential conductance and the quasi-particle interference spectrum-however, has been complicated by the fact that electrons tunneling from the STS tip into the system can tunnel either into the heavy magnetic moment or the light conduction band states. In this article, we briefly review the theoretical progress made in understanding how quantum interference between these two tunneling paths affects the experimental STS results. We show how this theoretical insight has allowed us to interpret the results of STS experiments on a series of heavy fermion materials providing detailed knowledge of their complex electronic structure. It is this knowledge that is a conditio sine qua non for developing a deeper understanding of the fascinating properties exhibited by heavy fermion materials, ranging from unconventional superconductivity to non-Fermi-liquid behavior in the vicinity of quantum critical points.
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Affiliation(s)
- Dirk K Morr
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
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23
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Abstract
The second-order phase transition into a hidden order phase in URu2Si2 goes along with an order parameter that is still a mystery, despite 30 years of research. However, it is understood that the symmetry of the order parameter must be related to the symmetry of the low-lying local electronic [Formula: see text]-states. Here, we present results of a spectroscopic technique, namely core-level nonresonant inelastic X-ray scattering (NIXS). This method allows for the measurement of local high-multipole excitations and is bulk-sensitive. The observed anisotropy of the scattering function unambiguously shows that the 5[Formula: see text] ground-state wave function is composed mainly of the [Formula: see text] with majority [Formula: see text] = [Formula: see text] + [Formula: see text] and/or [Formula: see text] singlet states. The incomplete dichroism indicates the possibility that quantum states of other irreducible representation are mixed into the ground state.
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24
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Kung HH, Ran S, Kanchanavatee N, Krapivin V, Lee A, Mydosh JA, Haule K, Maple MB, Blumberg G. Analogy Between the "Hidden Order" and the Orbital Antiferromagnetism in URu_{2-x}Fe_{x}Si_{2}. PHYSICAL REVIEW LETTERS 2016; 117:227601. [PMID: 27925725 DOI: 10.1103/physrevlett.117.227601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Indexed: 06/06/2023]
Abstract
We study URu_{2-x}Fe_{x}Si_{2}, in which two types of staggered phases compete at low temperature as the iron concentration x is varied: the nonmagnetic "hidden order" (HO) phase below the critical concentration x_{c}, and unconventional antiferromagnetic (AFM) phase above x_{c}. By using polarization resolved Raman spectroscopy, we detect a collective mode of pseudovectorlike A_{2g} symmetry whose energy continuously evolves with increasing x; it monotonically decreases in the HO phase until it vanishes at x=x_{c}, and then reappears with increasing energy in the AFM phase. The mode's evolution provides direct evidence for a unified order parameter for both nonmagnetic and magnetic phases arising from the orbital degrees-of-freedom of the uranium-5f electrons.
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Affiliation(s)
- H-H Kung
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - S Ran
- Department of Physics, University of California San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, USA
| | - N Kanchanavatee
- Department of Physics, University of California San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, USA
| | - V Krapivin
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - A Lee
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - J A Mydosh
- Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, The Netherlands
| | - K Haule
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - M B Maple
- Department of Physics, University of California San Diego, La Jolla, California 92093, USA
- Center for Advanced Nanoscience, University of California San Diego, La Jolla, California 92093, USA
| | - G Blumberg
- Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
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25
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Xiao H, Gao B, Ma YH, Li XJ, Mu G, Hu T. Superconducting fluctuation effect in CaFe0.88Co0.12AsF. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:455701. [PMID: 27619794 DOI: 10.1088/0953-8984/28/45/455701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF single crystals. Superconducting fluctuations, featured by magnetic field enhanced and exponential temperature dependent diamagnetism, are observed above the superconducting transition temperature T c, which is similar to that of cuprate superconductors, but less pronounced. In addition, the ratio of T c versus superfluid density follows well the Uemura line of high-T c cuprates, which suggests the exotic nature of the superconductivity in CaFe0.88Co0.12AsF.
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Affiliation(s)
- H Xiao
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, People's Republic of China
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26
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Knafo W, Duc F, Bourdarot F, Kuwahara K, Nojiri H, Aoki D, Billette J, Frings P, Tonon X, Lelièvre-Berna E, Flouquet J, Regnault LP. Field-induced spin-density wave beyond hidden order in URu 2Si 2. Nat Commun 2016; 7:13075. [PMID: 27762260 PMCID: PMC5080431 DOI: 10.1038/ncomms13075] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 08/31/2016] [Indexed: 11/09/2022] Open
Abstract
URu2Si2 is one of the most enigmatic strongly correlated electron systems and offers a fertile testing ground for new concepts in condensed matter science. In spite of >30 years of intense research, no consensus on the order parameter of its low-temperature hidden-order phase exists. A strong magnetic field transforms the hidden order into magnetically ordered phases, whose order parameter has also been defying experimental observation. Here, thanks to neutron diffraction under pulsed magnetic fields up to 40 T, we identify the field-induced phases of URu2Si2 as a spin-density-wave state. The transition to the spin-density wave represents a unique touchstone for understanding the hidden-order phase. An intimate relationship between this magnetic structure, the magnetic fluctuations and the Fermi surface is emphasized, calling for dedicated band-structure calculations. The strongly-correlated electron system URu2Si2 possesses a hidden-order phase whose order parameter remains unidentified. Here, the authors demonstrate the development of spin-density-wave phases in URu2Si2 under high magnetic fields, providing a potential in-road to understanding this system.
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Affiliation(s)
- W Knafo
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228, CNRS-UPS-INSA-UGA, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - F Duc
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228, CNRS-UPS-INSA-UGA, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - F Bourdarot
- Service de Modélisation et d'Exploration des Matériaux, Université Grenoble Alpes et Commissariat á l'Energie Atomique, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - K Kuwahara
- Institute of Quantum Beam Science, Ibaraki University, Mito 310-8512, Japan
| | - H Nojiri
- Institute for Materials Research, Tohoku University, Sendai 980-8578, Japan
| | - D Aoki
- Institute for Materials Research, Tohoku University, Ibaraki 311-1313, Japan.,Service Photonique, Electronique et Ingénierie Quantiques, Université Grenoble Alpes et Commissariat à l'Energie Atomique, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - J Billette
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228, CNRS-UPS-INSA-UGA, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - P Frings
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228, CNRS-UPS-INSA-UGA, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - X Tonon
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, France
| | - E Lelièvre-Berna
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, France
| | - J Flouquet
- Service Photonique, Electronique et Ingénierie Quantiques, Université Grenoble Alpes et Commissariat à l'Energie Atomique, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - L-P Regnault
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, France
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27
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Trinh J, Brück E, Siegrist T, Flint R, Chandra P, Coleman P, Ramirez AP. Thermodynamic Measurement of Angular Anisotropy at the Hidden Order Transition of URu_{2}Si_{2}. PHYSICAL REVIEW LETTERS 2016; 117:157201. [PMID: 27768324 DOI: 10.1103/physrevlett.117.157201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Indexed: 06/06/2023]
Abstract
The heavy fermion compound URu_{2}Si_{2} continues to attract great interest due to the unidentified hidden order it develops below 17.5 K. The unique Ising character of the spin fluctuations and low-temperature quasiparticles is well established. We present detailed measurements of the angular anisotropy of the nonlinear magnetization that reveal a cos^{4}θ Ising anisotropy both at and above the ordering transition. With Landau theory, we show this implies a strongly Ising character of the itinerant hidden order parameter.
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Affiliation(s)
- Jennifer Trinh
- Physics Department, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Ekkes Brück
- Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, TU Delft Mekelweg, 15, 2629 JB Delft, Netherlands
| | - Theo Siegrist
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
- Department of Chemistry and Biomedical Engineering, Florida State University, Tallahassee, Florida 32310, USA
| | - Rebecca Flint
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Premala Chandra
- Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Piers Coleman
- Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Physics, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | - Arthur P Ramirez
- Physics Department, University of California Santa Cruz, Santa Cruz, California 95064, USA
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28
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Giant superconducting fluctuations in the compensated semimetal FeSe at the BCS-BEC crossover. Nat Commun 2016; 7:12843. [PMID: 27687782 PMCID: PMC5056430 DOI: 10.1038/ncomms12843] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/03/2016] [Indexed: 11/24/2022] Open
Abstract
The physics of the crossover between weak-coupling Bardeen–Cooper–Schrieffer (BCS) and strong-coupling Bose–Einstein condensate (BEC) limits gives a unified framework of quantum-bound (superfluid) states of interacting fermions. This crossover has been studied in the ultracold atomic systems, but is extremely difficult to be realized for electrons in solids. Recently, the superconducting semimetal FeSe with a transition temperature Tc=8.5 K has been found to be deep inside the BCS–BEC crossover regime. Here we report experimental signatures of preformed Cooper pairing in FeSe, whose energy scale is comparable to the Fermi energies. In stark contrast to usual superconductors, large non-linear diamagnetism by far exceeding the standard Gaussian superconducting fluctuations is observed below T*∼20 K, providing thermodynamic evidence for prevailing phase fluctuations of superconductivity. Nuclear magnetic resonance and transport data give evidence of pseudogap formation at ∼T*. The multiband superconductivity along with electron–hole compensation in FeSe may highlight a novel aspect of the BCS–BEC crossover physics. The crossover between the weak-coupling limit and strong-coupling limit provides important information for quantum bound states of interacting fermions. Here, Kasahara et al. report thermodynamic evidence for prevailing phase fluctuations of superconductivity, highlighting unusual normal state in the BCS-BEC crossover regime.
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29
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Xiao H, Gao B, Ma YH, Li XJ, Mu G, Hu T. Angular dependent torque measurements on CaFe0.88Co0.12AsF. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:325701. [PMID: 27346165 DOI: 10.1088/0953-8984/28/32/325701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF (Ca1 1 1 1) single crystals. In the normal state, the torque data shows [Formula: see text] angular dependence and H (2) magnetic field dependence, as a result of paramagnetism. In the mixed state, the torque signal is a combination of the vortex torque and paramagnetic torque, and the former allows the determination of the anisotropy parameter γ. At T = 11.5 K, γ (11.5 K ≃ 0.5 T c) = 19.1, which is similar to the result of SmFeAsO0.8F0.2, [Formula: see text] at [Formula: see text]. So the 11 1 1 is more anisotropic compared to 11 and 122 families of iron-based superconductors. This may suggest that the electronic coupling between layers in 1 1 1 1 is less effective than in 11 and 122 families.
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Affiliation(s)
- H Xiao
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, People's Republic of China
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30
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Kallin C, Berlinsky J. Chiral superconductors. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:054502. [PMID: 27088452 DOI: 10.1088/0034-4885/79/5/054502] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.
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31
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Gallagher A, Chen KW, Moir CM, Cary SK, Kametani F, Kikugawa N, Graf D, Albrecht-Schmitt TE, Riggs SC, Shekhter A, Baumbach RE. Unfolding the physics of URu2Si2 through silicon to phosphorus substitution. Nat Commun 2016; 7:10712. [PMID: 26891903 PMCID: PMC4762885 DOI: 10.1038/ncomms10712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 01/12/2016] [Indexed: 11/15/2022] Open
Abstract
The heavy fermion intermetallic compound URu2Si2 exhibits a hidden-order phase below the temperature of 17.5 K, which supports both anomalous metallic behavior and unconventional superconductivity. While these individual phenomena have been investigated in detail, it remains unclear how they are related to each other and to what extent uranium f-electron valence fluctuations influence each one. Here we use ligand site substituted URu2Si2-xPx to establish their evolution under electronic tuning. We find that while hidden order is monotonically suppressed and destroyed for x≤0.035, the superconducting strength evolves non-monotonically with a maximum near x≈0.01 and that superconductivity is destroyed near x≈0.028. This behavior reveals that hidden order depends strongly on tuning outside of the U f-electron shells. It also suggests that while hidden order provides an environment for superconductivity and anomalous metallic behavior, it's fluctuations may not be solely responsible for their progression. The heavy fermion compound URu2Si2 displays a hidden order phase and superconductivity at low temperatures. Here, the authors perform substitution studies—partially replacing silicon with phosphorus—and study the effects on hidden order and superconductivity.
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Affiliation(s)
- A Gallagher
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - K-W Chen
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - C M Moir
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - S K Cary
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - F Kametani
- Applied Superconductivity Center, Florida State University, Tallahassee, Florida 32310, USA
| | - N Kikugawa
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.,National Institute for Materials Science 3-13 Sakura, Tsukuba 305-0003, Japan
| | - D Graf
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - T E Albrecht-Schmitt
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - S C Riggs
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - A Shekhter
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - R E Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
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32
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Kung HH, Baumbach RE, Bauer ED, Thorsmølle VK, Zhang WL, Haule K, Mydosh JA, Blumberg G. Chirality density wave of the “hidden order” phase in URu
2
Si
2. Science 2015; 347:1339-42. [DOI: 10.1126/science.1259729] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- H.-H. Kung
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - R. E. Baumbach
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - E. D. Bauer
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - V. K. Thorsmølle
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - W.-L. Zhang
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - K. Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
| | - J. A. Mydosh
- Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden, Netherlands
| | - G. Blumberg
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
- National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
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33
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Evidence for a nematic component to the hidden-order parameter in URu2Si2 from differential elastoresistance measurements. Nat Commun 2015; 6:6425. [PMID: 25742938 DOI: 10.1038/ncomms7425] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 01/28/2015] [Indexed: 11/08/2022] Open
Abstract
For materials that harbour a continuous phase transition, the susceptibility of the material to various fields can be used to understand the nature of the fluctuating order and hence the nature of the ordered state. Here we use anisotropic biaxial strain to probe the nematic susceptibility of URu2Si2, a heavy fermion material for which the nature of the low temperature 'hidden order' state has defied comprehensive understanding for over 30 years. Our measurements reveal that the fluctuating order has a nematic component, confirming reports of twofold anisotropy in the broken symmetry state and strongly constraining theoretical models of the hidden-order phase.
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34
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Buhot J, Méasson MA, Gallais Y, Cazayous M, Sacuto A, Lapertot G, Aoki D. Symmetry of the excitations in the hidden order state of URu2Si2. PHYSICAL REVIEW LETTERS 2014; 113:266405. [PMID: 25615363 DOI: 10.1103/physrevlett.113.266405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Indexed: 06/04/2023]
Abstract
We perform polarized electronic Raman scattering on URu2Si2 single crystals at low temperature down to 8 K in the hidden-order state and under a magnetic field up to 10 T. The hidden-order state is characterized by a sharp excitation at 1.7 meV and a gap in the electronic continuum below 6.8 meV. Both Raman signatures are of pure A2g symmetry. By comparing the behavior of the Raman sharp excitation and the neutron resonance at Q0=(0,0,1), we provide new evidence, constrained by selection rules of the two probes, that the hidden-order state breaks the translational symmetry along the c axis such that Γ and Z points fold on top of each other. The observation of these distinct Raman features with a peculiar A2g symmetry as a signature of the hidden-order phase places strong constraints on current theories of the hidden-order in URu2Si2.
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Affiliation(s)
- J Buhot
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - M-A Méasson
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - Y Gallais
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - M Cazayous
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - A Sacuto
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - G Lapertot
- Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble, France and CEA, INAC-SPSMS, F-38000 Grenoble, France
| | - D Aoki
- Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble, France and CEA, INAC-SPSMS, F-38000 Grenoble, France
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35
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Tonegawa S, Kasahara S, Fukuda T, Sugimoto K, Yasuda N, Tsuruhara Y, Watanabe D, Mizukami Y, Haga Y, Matsuda TD, Yamamoto E, Onuki Y, Ikeda H, Matsuda Y, Shibauchi T. Direct observation of lattice symmetry breaking at the hidden-order transition in URu2Si2. Nat Commun 2014; 5:4188. [PMID: 24943003 DOI: 10.1038/ncomms5188] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 05/22/2014] [Indexed: 11/09/2022] Open
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36
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Sakai H, Tokunaga Y, Kambe S, Urbano RR, Suzuki MT, Kuhns PL, Reyes AP, Tobash PH, Ronning F, Bauer ED, Thompson JD. Emergent antiferromagnetism out of the "hidden-order" state in URu2Si2: high magnetic field nuclear magnetic resonance to 40 T. PHYSICAL REVIEW LETTERS 2014; 112:236401. [PMID: 24972218 DOI: 10.1103/physrevlett.112.236401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Indexed: 06/03/2023]
Abstract
Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.
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Affiliation(s)
- H Sakai
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Y Tokunaga
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - S Kambe
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - R R Urbano
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, SP, Brazil and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - M-T Suzuki
- CCSE, Japan Atomic Energy Agency, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8587, Japan
| | - P L Kuhns
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - A P Reyes
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - P H Tobash
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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37
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Shivaram BS. Note: nonlinear susceptibility from high DC field torque magnetometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:046107. [PMID: 24784685 DOI: 10.1063/1.4870796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Torque magnetometry is a convenient technique to measure the magnetic properties of anisotropic materials. Advances in micromachining have made torque magnetometers precise and reliable even in adverse conditions such as very high magnetic fields and very low temperatures. In most applications with such magnetometers the measured torque signals are used to arrive at the linear magnetic susceptibility. In this short note we extend torque magnetometry to measure nonlinear susceptibilities and illustrate our methods with representative data on the heavy fermion compound UPt3.
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Affiliation(s)
- B S Shivaram
- Department of Physics, University of Virginia, Charlottesville, Virginia 22901, USA
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38
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Gallais Y, Fernandes RM, Paul I, Chauvière L, Yang YX, Méasson MA, Cazayous M, Sacuto A, Colson D, Forget A. Observation of incipient charge nematicity in Ba(Fe(1-x)Co(x))2As2. PHYSICAL REVIEW LETTERS 2013; 111:267001. [PMID: 24483810 DOI: 10.1103/physrevlett.111.267001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Indexed: 06/03/2023]
Abstract
Using electronic Raman spectroscopy, we report direct measurements of charge nematic fluctuations in the tetragonal phase of strain-free Ba(Fe(1-x)Co(x))2As2 single crystals. The strong enhancement of the Raman response at low temperatures unveils an underlying charge nematic state that extends to superconducting compositions and which has hitherto remained unnoticed. Comparison between the extracted charge nematic susceptibility and the elastic modulus allows us to disentangle the charge contribution to the nematic instability, and to show that charge nematic fluctuations are weakly coupled to the lattice.
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Affiliation(s)
- Y Gallais
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - R M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - I Paul
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - L Chauvière
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - Y-X Yang
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - M-A Méasson
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - M Cazayous
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - A Sacuto
- Laboratoire Matériaux et Phénomenes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, Bâtiment Condorcet, 75205 Paris Cedex 13, France
| | - D Colson
- CEA-Saclay, IRAMIS, Service de Physique de l'Etat Condensé (SPEC URA CNRS 2464), F-91191 Gif-sur-Yvette, France
| | - A Forget
- CEA-Saclay, IRAMIS, Service de Physique de l'Etat Condensé (SPEC URA CNRS 2464), F-91191 Gif-sur-Yvette, France
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39
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Yoshida R, Tsubota K, Ishiga T, Sunagawa M, Sonoyama J, Aoki D, Flouquet J, Wakita T, Muraoka Y, Yokoya T. Translational symmetry breaking and gapping of heavy-quasiparticle pocket in URu₂Si₂. Sci Rep 2013; 3:2750. [PMID: 24084937 PMCID: PMC3788364 DOI: 10.1038/srep02750] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/06/2013] [Indexed: 11/09/2022] Open
Abstract
URu2Si2 is a uranium compound that exhibits a so-called ‘hidden-order’ transition at ~17.5 K. However, the order parameter of this second-order transition as well as many of its microscopic properties remain unclarified despite considerable research. One of the key questions in this regard concerns the type of spontaneous symmetry breaking occurring at the transition; although rotational symmetry breaking has been detected, it is not clear whether another type of symmetry breaking also occurs. Another key question concerns the property of Fermi-surface gapping in the momentum space. Here we address these key questions by a momentum-dependent observation of electronic states at the transition employing ultrahigh-resolution three-dimensional angle-resolved photoemission spectroscopy. Our results provide compelling evidence of the spontaneous breaking of the lattice's translational symmetry and particle-hole asymmetric gapping of a heavy quasiparticle pocket at the transition.
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Affiliation(s)
- Rikiya Yoshida
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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40
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Meng JQ, Oppeneer PM, Mydosh JA, Riseborough PS, Gofryk K, Joyce JJ, Bauer ED, Li Y, Durakiewicz T. Imaging the three-dimensional Fermi-surface pairing near the hidden-order transition in URu2Si2 using angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2013; 111:127002. [PMID: 24093292 DOI: 10.1103/physrevlett.111.127002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Indexed: 06/02/2023]
Abstract
We report angle-resolved photoemission spectroscopy experiments probing deep into the hidden-order state of URu(2)Si(2), utilizing tunable photon energies with sufficient energy and momentum resolution to detect the near Fermi-surface (FS) behavior. Our results reveal (i) the full itinerancy of the 5f electrons, (ii) the crucial three-dimensional k-space nature of the FS and its critical nesting vectors, in good comparison with density-functional theory calculations, and (iii) the existence of hot-spot lines and pairing of states at the FS, leading to FS gapping in the hidden-order phase.
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Affiliation(s)
- Jian-Qiao Meng
- Los Alamos National Laboratory, Condensed Matter and Magnet Science Group, Los Alamos, New Mexico 87545, USA
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41
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Guarnaccia G, Noce C. Nematic order in a degenerate Hubbard model with spin-orbit coupling. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:345602. [PMID: 23896700 DOI: 10.1088/0953-8984/25/34/345602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Using Bogoliubov's inequality we rigorously show that the multiorbital Hubbard model with narrow bands, even in the presence of spin-orbit coupling, does not exhibit long-range nematic order, in low dimensions. This result holds at any finite temperature for both repulsive and attractive Coulomb interactions, with and without spin-orbit coupling.
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Affiliation(s)
- Giuseppe Guarnaccia
- Dipartimento di Fisica E R Caianiello, Università di Salerno, I-84084 Fisciano (Salerno), Italy
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42
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Kambe S, Tokunaga Y, Sakai H, Matsuda TD, Haga Y, Fisk Z, Walstedt RE. NMR study of in-plane twofold ordering in URu(2)Si(2). PHYSICAL REVIEW LETTERS 2013; 110:246406. [PMID: 25165947 DOI: 10.1103/physrevlett.110.246406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Indexed: 06/03/2023]
Abstract
We report (29)Si NMR spectra and Knight shift measurements as a function of applied field orientation in the (001) basal plane of URu(2)Si(2). Observed linewidth oscillations confirm the in-plane twofold ordered domain state observed in recent magnetic susceptibility measurements. Analysis of our linewidth data leads to estimate ∼ 0.4% for the twofold intrinsic (monodomain) susceptibility anisotropy in the basal plane, a value ∼ 15 times smaller than that obtained from recent susceptibility measurements.
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Affiliation(s)
- S Kambe
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan
| | - Y Tokunaga
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan
| | - H Sakai
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan
| | - T D Matsuda
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan
| | - Y Haga
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan
| | - Z Fisk
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195, Japan and Department of Physics and Astronomy, University of California Irvine, Irvine, California 97697, USA
| | - R E Walstedt
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109, USA
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43
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Jiang S, Jeevan HS, Dong J, Gegenwart P. Thermopower as a sensitive probe of electronic nematicity in iron pnictides. PHYSICAL REVIEW LETTERS 2013; 110:067001. [PMID: 23432292 DOI: 10.1103/physrevlett.110.067001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Indexed: 06/01/2023]
Abstract
We study the in-plane anisotropy of the thermoelectric power and electrical resistivity on detwinned single crystals of isovalent substituted EuFe(2)(As(1-x)P(x))(2). Compared to the resistivity anisotropy, the thermopower anisotropy is more pronounced and clearly visible already at temperatures much above the structural and magnetic phase transitions. Most remarkably, the thermopower anisotropy changes sign below the structural transition. This is associated with the interplay of two contributions due to anisotropic scattering and orbital polarization, which dominate at high and low temperatures, respectively.
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Affiliation(s)
- Shuai Jiang
- I. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
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44
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Watanabe D, Yamashita M, Tonegawa S, Oshima Y, Yamamoto HM, Kato R, Sheikin I, Behnia K, Terashima T, Uji S, Shibauchi T, Matsuda Y. Novel Pauli-paramagnetic quantum phase in a Mott insulator. Nat Commun 2013; 3:1090. [PMID: 23011144 DOI: 10.1038/ncomms2082] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 08/22/2012] [Indexed: 11/09/2022] Open
Abstract
In Mott insulators, the strong electron-electron Coulomb repulsion localizes electrons. In dimensions greater than one, their spins are usually ordered antiferromagnetically at low temperatures. Geometrical frustrations can destroy this long-range order, leading to exotic quantum spin liquid states. However, their magnetic ground states have been a long-standing mystery. Here we show that a quantum spin liquid state in the organic Mott insulator EtMe(3)Sb[Pd(dmit)(2)](2) (where Et is C(2)H(5)-, Me is CH(3)-, and dmit is 1,3-dithiole-2-thione-4,5-dithiolate) with two-dimensional triangular lattice has Pauli-paramagnetic-like low-energy excitations, which are a hallmark of itinerant fermions. Our torque magnetometry down to low temperatures (30 mK) up to high fields (32 T) reveals distinct residual paramagnetic susceptibility comparable to that in a half-filled two-dimensional metal, demonstrating the magnetically gapless nature of the ground state. Moreover, our results are robust against deuteration, pointing toward the emergence of an extended 'quantum critical phase', in which low-energy spin excitations behave as in paramagnetic metals with Fermi surface, despite the frozen charge degree of freedom.
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Affiliation(s)
- D Watanabe
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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45
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Chandra P, Coleman P, Flint R. Hastatic order in the heavy-fermion compound URu2Si2. Nature 2013; 493:621-6. [PMID: 23364741 DOI: 10.1038/nature11820] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 11/27/2012] [Indexed: 11/09/2022]
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46
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Das T. Spin-orbit density wave induced hidden topological order in URu2Si2. Sci Rep 2012; 2:596. [PMID: 22916332 PMCID: PMC3424526 DOI: 10.1038/srep00596] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/06/2012] [Indexed: 11/09/2022] Open
Abstract
The conventional order parameters in quantum matters are often characterized by 'spontaneous' broken symmetries. However, sometimes the broken symmetries may blend with the invariant symmetries to lead to mysterious emergent phases. The heavy fermion metal URu2Si2 is one such example, where the order parameter responsible for a second-order phase transition at Th=17.5 K has remained a long-standing mystery. Here we propose via ab-initio calculation and effective model that a novel spin-orbit density wave in the f-states is responsible for the hidden-order phase in URu2Si2. The staggered spin-orbit order spontaneously breaks rotational, and translational symmetries while time-reversal symmetry remains intact. Thus it is immune to pressure, but can be destroyed by magnetic field even at T=0 K, that means at a quantum critical point. We compute topological index of the order parameter to show that the hidden order is topologically invariant. Finally, some verifiable predictions are presented.
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Affiliation(s)
- Tanmoy Das
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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47
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Ressouche E, Ballou R, Bourdarot F, Aoki D, Simonet V, Fernandez-Diaz MT, Stunault A, Flouquet J. Hidden order in URu2Si2 unveiled. PHYSICAL REVIEW LETTERS 2012; 109:067202. [PMID: 23006299 DOI: 10.1103/physrevlett.109.067202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Indexed: 06/01/2023]
Abstract
We report on measurements, by polarized neutron elastic scattering, of the magnetization distribution induced in a single crystal of URu2Si2 under a magnetic field applied along the tetragonal c axis. A subtle change in this distribution, revealed by maximum entropy analysis of the data, is found when the temperature is decreased to the range of the hidden order. An analysis in terms of U(4+) ionic states reveals that this change is a fingerprint of a freezing of rank 5 multipoles, i.e., dotriacontapoles.
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Affiliation(s)
- E Ressouche
- SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble F-38054, France
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48
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Chu JH, Kuo HH, Analytis JG, Fisher IR. Divergent Nematic Susceptibility in an Iron Arsenide Superconductor. Science 2012; 337:710-2. [DOI: 10.1126/science.1221713] [Citation(s) in RCA: 402] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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49
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Tonegawa S, Hashimoto K, Ikada K, Lin YH, Shishido H, Haga Y, Matsuda TD, Yamamoto E, Onuki Y, Ikeda H, Matsuda Y, Shibauchi T. Cyclotron resonance in the hidden-order phase of URu2Si2. PHYSICAL REVIEW LETTERS 2012; 109:036401. [PMID: 22861875 DOI: 10.1103/physrevlett.109.036401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Indexed: 06/01/2023]
Abstract
We report the first observation of cyclotron resonance in the hidden-order phase of ultraclean URu2Si2 crystals, which allows the full determination of angle-dependent electron-mass structure of the main Fermi-surface sheets. We find an anomalous splitting of the sharpest resonance line under in-plane magnetic-field rotation. This is most naturally explained by the domain formation, which breaks the fourfold rotational symmetry of the underlying tetragonal lattice. The results reveal the emergence of an in-plane mass anisotropy with hot spots along the [110] direction, which can account for the anisotropic in-plane magnetic susceptibility reported recently. This is consistent with the "nematic" Fermi liquid state, in which itinerant electrons have unidirectional correlations.
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Affiliation(s)
- S Tonegawa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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50
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Electronic nematicity above the structural and superconducting transition in BaFe2(As(1-x)P(x))2. Nature 2012; 486:382-5. [PMID: 22722198 DOI: 10.1038/nature11178] [Citation(s) in RCA: 369] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 05/01/2012] [Indexed: 11/08/2022]
Abstract
Electronic nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice, has been observed in the iron pnictide and copper oxide high-temperature superconductors. Whether nematicity plays an equally important role in these two systems is highly controversial. In iron pnictides, the nematicity has usually been associated with the tetragonal-to-orthorhombic structural transition at temperature T(s). Although recent experiments have provided hints of nematicity, they were performed either in the low-temperature orthorhombic phase or in the tetragonal phase under uniaxial strain, both of which break the 90° rotational C(4) symmetry. Therefore, the question remains open whether the nematicity can exist above T(s) without an external driving force. Here we report magnetic torque measurements of the isovalent-doping system BaFe(2)(As(1-x)P(x))(2), showing that the nematicity develops well above T(s) and, moreover, persists to the non-magnetic superconducting regime, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides. By combining these results with synchrotron X-ray measurements, we identify two distinct temperatures-one at T*, signifying a true nematic transition, and the other at T(s) (<T*), which we show not to be a true phase transition, but rather what we refer to as a 'meta-nematic transition', in analogy to the well-known meta-magnetic transition in the theory of magnetism.
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