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Mou Y, Chen H, Liu J, Lan Q, Wang J, Zhang C, Wang Y, Gu J, Zhao T, Jiang X, Shi W, Zhang C. Gate-Tunable Quantum Acoustoelectric Transport in Graphene. NANO LETTERS 2024; 24:4625-4632. [PMID: 38568748 DOI: 10.1021/acs.nanolett.4c00774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Transport probes the motion of quasi-particles in response to external excitations. Apart from the well-known electric and thermoelectric transport, acoustoelectric transport induced by traveling acoustic waves has rarely been explored. Here, by adopting hybrid nanodevices integrated with piezoelectric substrates, we establish a simple design of acoustoelectric transport with gate tunability. We fabricate dual-gated acoustoelectric devices based on hBN-encapsulated graphene on LiNbO3. Longitudinal and transverse acoustoelectric voltages are generated by launching a pulsed surface acoustic wave. The gate dependence of zero-field longitudinal acoustoelectric signal presents strikingly similar profiles to that of Hall resistivity, providing a valid approach for extracting carrier density without magnetic field. In magnetic fields, acoustoelectric quantum oscillations appear due to Landau quantization, which are more robust and pronounced than Shubnikov-de Haas oscillations. Our work demonstrates a feasible acoustoelectric setup with gate tunability, which can be extended to the broad scope of various van der Waals materials.
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Affiliation(s)
- Yicheng Mou
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Haonan Chen
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Jiaqi Liu
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Qing Lan
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Jiayu Wang
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Chuanxin Zhang
- Department of Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China
| | - Yuxiang Wang
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Jiaming Gu
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Tuoyu Zhao
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Xue Jiang
- Department of Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China
| | - Wu Shi
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Cheng Zhang
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
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2
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Melcer RA, Gil A, Paul AK, Tiwari P, Umansky V, Heiblum M, Oreg Y, Stern A, Berg E. Heat conductance of the quantum Hall bulk. Nature 2024; 625:489-493. [PMID: 38172641 DOI: 10.1038/s41586-023-06858-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 11/10/2023] [Indexed: 01/05/2024]
Abstract
The quantum Hall effect is a prototypical realization of a topological state of matter. It emerges from a subtle interplay between topology, interactions and disorder1-9. The disorder enables the formation of localized states in the bulk that stabilize the quantum Hall states with respect to the magnetic field and carrier density3. Still, the details of the localized states and their contribution to transport remain beyond the reach of most experimental techniques10-31. Here we describe an extensive study of the bulk's heat conductance. Using a novel 'multiterminal' short device (on a scale of 10 µm), we separate the longitudinal thermal conductance, [Formula: see text] (owing to the bulk's contribution), from the topological transverse value [Formula: see text] by eliminating the contribution of the edge modes24. When the magnetic field is tuned away from the conductance plateau centre, the localized states in the bulk conduct heat efficiently ([Formula: see text]), whereas the bulk remains electrically insulating. Fractional states in the first excited Landau level, such as the [Formula: see text] and [Formula: see text], conduct heat throughout the plateau with a finite [Formula: see text]. We propose a theoretical model that identifies the localized states as the cause of the finite heat conductance, agreeing qualitatively with our experimental findings.
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Affiliation(s)
- Ron Aharon Melcer
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Avigail Gil
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Arup Kumar Paul
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Priya Tiwari
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Vladimir Umansky
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Moty Heiblum
- Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
| | - Yuval Oreg
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Ady Stern
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Erez Berg
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
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3
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Chudzinski P, Berben M, Xu X, Wakeham N, Bernáth B, Duffy C, Hinlopen RDH, Hsu YT, Wiedmann S, Tinnemans P, Jin R, Greenblatt M, Hussey NE. Emergent symmetry in a low-dimensional superconductor on the edge of Mottness. Science 2023; 382:792-796. [PMID: 37972183 DOI: 10.1126/science.abp8948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 09/29/2023] [Indexed: 11/19/2023]
Abstract
Upon cooling, condensed-matter systems typically transition into states of lower symmetry. The converse-i.e., the emergence of higher symmetry at lower temperatures-is extremely rare. In this work, we show how an unusually isotropic magnetoresistance in the highly anisotropic, one-dimensional conductor Li0.9Mo6O17 and its temperature dependence can be interpreted as a renormalization group (RG) flow toward a so-called separatrix. This approach is equivalent to an emergent symmetry in the system. The existence of two distinct ground states, Mott insulator and superconductor, can then be traced back to two opposing RG trajectories. By establishing a direct link between quantum field theory and an experimentally measurable quantity, we uncover a path through which emergent symmetry might be identified in other candidate materials.
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Affiliation(s)
- P Chudzinski
- School of Mathematics and Physics, Queen's University Belfast, Belfast, UK
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - M Berben
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - Xiaofeng Xu
- Key Laboratory of Quantum Precision Measurement of Zhejiang Province, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, China
| | - N Wakeham
- Center for Space Sciences and Technology, University of Maryland Baltimore, Baltimore, MD, USA
| | - B Bernáth
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - C Duffy
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - R D H Hinlopen
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, UK
| | - Yu-Te Hsu
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - S Wiedmann
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - P Tinnemans
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - Rongying Jin
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, SC, USA
| | - M Greenblatt
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - N E Hussey
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Nijmegen, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, UK
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4
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Torres F, Basaran AC, Schuller IK. Thermal Management in Neuromorphic Materials, Devices, and Networks. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205098. [PMID: 36067752 DOI: 10.1002/adma.202205098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Machine learning has experienced unprecedented growth in recent years, often referred to as an "artificial intelligence revolution." Biological systems inspire the fundamental approach for this new computing paradigm: using neural networks to classify large amounts of data into sorting categories. Current machine-learning schemes implement simulated neurons and synapses on standard computers based on a von Neumann architecture. This approach is inefficient in energy consumption, and thermal management, motivating the search for hardware-based systems that imitate the brain. Here, the present state of thermal management of neuromorphic computing technology and the challenges and opportunities of the energy-efficient implementation of neuromorphic devices are considered. The main features of brain-inspired computing and quantum materials for implementing neuromorphic devices are briefly described, the brain criticality and resistive switching-based neuromorphic devices are discussed, the energy and electrical considerations for spiking-based computation are presented, the fundamental features of the brain's thermal regulation are addressed, the physical mechanisms for thermal management and thermoelectric control of materials and neuromorphic devices are analyzed, and challenges and new avenues for implementing energy-efficient computing are described.
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Affiliation(s)
- Felipe Torres
- Physics Department, Faculty of Science, University of Chile, 653, Santiago, 7800024, Chile
- Center of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, Santiago, 9170124, Chile
| | - Ali C Basaran
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, CA, 92093, USA
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5
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Sharma V, Okram GS, Kuo YK. Metal to insulator transition, colossal Seebeck coefficient and large violation of Wiedemann-Franz law in nanoscale granular nickel. NANOTECHNOLOGY 2022; 34:035702. [PMID: 36228508 DOI: 10.1088/1361-6528/ac99e6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
We report on the electrical and thermal transport properties of nickel nanoparticles with crystallite size from 23.1 ± 0.3 to 1.3 ± 0.3 nm. These nanoparticles show a systematic metal to insulator transition with the change in the conduction type fromn- to p-type, colossal Seebeck coefficient of 1.87 ± 0.07 mV K-1, and ultralow thermal conductivity of 0.52 ± 0.05 W m-1K-1at 300 K as the crystallite size drops. The electrical resistivity analysis reveals a dramatic change in the electronic excitation spectrum indicating the opening of an energy gap, and cotunneling and Coulomb blockade of the charge carriers. Seebeck coefficient shows transport energy degradation of charge carriers as transport level moves away from the Fermi level with decrease in crystallite size. The Lorenz number rising to about four orders of magnitude in the metallic regimes with decrease in crystallite size, showing a large violation of the Wiedemann-Franz law in these compacted nickel nanoparticles. Such an observation provides the compelling confirmation for unconventional quasiparticle dynamics where the transport of charge and heat is independent of each other. Therefore, such nanoparticles provide an intriguing platform to tune the charge and heat transport, which may be useful for thermoelectrics and heat dissipation in nanocrystal array-based electronics.
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Affiliation(s)
- Vikash Sharma
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, Madhya Pradesh, India
- Department of Condensed Matter Physics & Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400005, India
| | - Gunadhor Singh Okram
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, Madhya Pradesh, India
| | - Yung-Kang Kuo
- Department of Physics, National Dong-Hwa University, Hualien 97401, Taiwan
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6
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Waissman J, Anderson LE, Talanov AV, Yan Z, Shin YJ, Najafabadi DH, Rezaee M, Feng X, Nocera DG, Taniguchi T, Watanabe K, Skinner B, Matveev KA, Kim P. Electronic thermal transport measurement in low-dimensional materials with graphene non-local noise thermometry. NATURE NANOTECHNOLOGY 2022; 17:166-173. [PMID: 34782778 DOI: 10.1038/s41565-021-01015-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
In low-dimensional systems, the combination of reduced dimensionality, strong interactions and topology has led to a growing number of many-body quantum phenomena. Thermal transport, which is sensitive to all energy-carrying degrees of freedom, provides a discriminating probe of emergent excitations in quantum materials and devices. However, thermal transport measurements in low dimensions are dominated by the phonon contribution of the lattice, requiring an experimental approach to isolate the electronic thermal conductance. Here we measured non-local voltage fluctuations in a multi-terminal device to reveal the electronic heat transported across a mesoscopic bridge made of low-dimensional materials. Using two-dimensional graphene as a noise thermometer, we measured the quantitative electronic thermal conductance of graphene and carbon nanotubes up to 70 K, achieving a precision of ~1% of the thermal conductance quantum at 5 K. Employing linear and nonlinear thermal transport, we observed signatures of energy transport mediated by long-range interactions in one-dimensional electron systems, in agreement with a theoretical model.
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Affiliation(s)
- Jonah Waissman
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Artem V Talanov
- Department of Physics, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Zhongying Yan
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Young J Shin
- Department of Physics, Harvard University, Cambridge, MA, USA
| | | | - Mehdi Rezaee
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Xiaowen Feng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Brian Skinner
- Department of Physics, The Ohio State University, Columbus, OH, USA
| | | | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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7
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Zhao M, Kim D, Lee YH, Yang H, Cho S. Quantum Sensing of Thermoelectric Power in Low-Dimensional Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2106871. [PMID: 34889480 DOI: 10.1002/adma.202106871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/26/2021] [Indexed: 06/13/2023]
Abstract
Thermoelectric power, has been extensively studied in low-dimensional materials where quantum confinement and spin textures can largely modulate thermopower generation. In addition to classical and macroscopic values, thermopower also varies locally over a wide range of length scales, and is fundamentally linked to electron wave functions and phonon propagation. Various experimental methods for the quantum sensing of localized thermopower have been suggested, particularly based on scanning probe microscopy. Here, critical advances in the quantum sensing of thermopower are introduced, from the atomic to the several-hundred-nanometer scales, including the unique role of low-dimensionality, defects, spins, and relativistic effects for optimized power generation. Investigating the microscopic nature of thermopower in quantum materials can provide insights useful for the design of advanced materials for future thermoelectric applications. Quantum sensing techniques for thermopower can pave the way to practical and novel energy devices for a sustainable society.
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Affiliation(s)
- Mali Zhao
- Interdisciplinary Materials Research Center, College of Materials Science and Engineering, Tongji University, Shanghai, 201804, People's Republic of China
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dohyun Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Young Hee Lee
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Suwon, 16419, Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Suyeon Cho
- Division of Chemical Engineering and Materials Science, Ewha Womans University, Seoul, 03760, Korea
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8
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Yi H, Bahng J, Park S, Dang DX, Sakong W, Kang S, Ahn BW, Kim J, Kim KK, Lim JT, Lim SC. Enhanced Electron Heat Conduction in TaS 3 1D Metal Wire. MATERIALS 2021; 14:ma14164477. [PMID: 34442999 PMCID: PMC8401328 DOI: 10.3390/ma14164477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/16/2022]
Abstract
The 1D wire TaS3 exhibits metallic behavior at room temperature but changes into a semiconductor below the Peierls transition temperature (Tp), near 210 K. Using the 3ω method, we measured the thermal conductivity κ of TaS3 as a function of temperature. Electrons dominate the heat conduction of a metal. The Wiedemann–Franz law states that the thermal conductivity κ of a metal is proportional to the electrical conductivity σ with a proportional coefficient of L0, known as the Lorenz number—that is, κ=σLoT. Our characterization of the thermal conductivity of metallic TaS3 reveals that, at a given temperature T, the thermal conductivity κ is much higher than the value estimated in the Wiedemann–Franz (W-F) law. The thermal conductivity of metallic TaS3 was approximately 12 times larger than predicted by W-F law, implying L=12L0. This result implies the possibility of an existing heat conduction path that the Sommerfeld theory cannot account for.
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Affiliation(s)
- Hojoon Yi
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
| | - Jaeuk Bahng
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Korea;
| | - Sehwan Park
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Dang Xuan Dang
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
| | - Wonkil Sakong
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Seungsu Kang
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
| | - Byung-wook Ahn
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Jungwon Kim
- Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Chudong-ro, Bongdong-eub, Seoul 55324, Korea;
| | - Ki Kang Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon 16419, Korea
| | - Jong Tae Lim
- Reality Devices Research Division, Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
- Correspondence: (J.T.L.); (S.C.L.)
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea; (H.Y.); (S.P.); (D.X.D.); (W.S.); (S.K.); (B.-w.A.); (K.K.K.)
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Korea;
- Correspondence: (J.T.L.); (S.C.L.)
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9
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Rycerz A. Wiedemann-Franz Law for Massless Dirac Fermions with Implications for Graphene. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2704. [PMID: 34063902 PMCID: PMC8196567 DOI: 10.3390/ma14112704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022]
Abstract
In the 2016 experiment by Crossno et al. the electronic contribution to the thermal conductivity of graphene was found to violate the well-known Wiedemann-Franz (WF) law for metals. At liquid nitrogen temperatures, the thermal to electrical conductivity ratio of charge-neutral samples was more than 10 times higher than predicted by the WF law, which was attributed to interactions between particles leading to collective behavior described by hydrodynamics. Here, we show, by adapting the handbook derivation of the WF law to the case of massless Dirac fermions, that significantly enhanced thermal conductivity should appear also in few- or even sub-kelvin temperatures, where the role of interactions can be neglected. The comparison with numerical results obtained within the Landauer-Büttiker formalism for rectangular and disk-shaped (Corbino) devices in ballistic graphene is also provided.
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Affiliation(s)
- Adam Rycerz
- Institute for Theoretical Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
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10
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Song Z, Li B, Xu C, Wu S, Qian B, Chen T, Biswas PK, Xu X, Sun J. Pressure engineering of the Dirac fermions in quasi-one-dimensional Tl 2Mo 6Se 6. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:215402. [PMID: 32032009 DOI: 10.1088/1361-648x/ab73a8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Topological band dispersions other than the standard Dirac or Weyl fermions have garnered the increasing interest in materials science. Among them, the cubic Dirac fermions were recently proposed in the family of quasi-one-dimensional (q-1D) conductors A2Mo6X6 (A = Na, K, In, Tl; X = S, Se, Te), where the band crossing is characterized by a linear dispersion in one k-space direction but the cubic dispersion in the plane perpendicular to it. It is not yet clear, however, how the external perturbations can alter these nontrivial carriers and ultimately induce a new distinct quantum phase. Here we study the evolution of Dirac fermions, in particular the cubic Dirac crossing, under external pressure in the representative q-1D Tl2Mo6Se6 via the first-principles calculations. Specifically, it is found that the topological properties, including the bulk Dirac crossings and the topological surface states, change progressively under pressure up to 50 GPa where it undergoes a structural transition from the hexagonal phase to body-centered tetragonal phase. Above 50 GPa, the system is more likely to be topologically trivial. Further, we also investigate its phonon spectra, which reveals a gradual depletion of the negative phonon modes with pressure, consistent with the more three-dimensional Fermi surface in the high-pressure phase. Our work may provide a useful guideline for further experimental search and the band engineering of the topologically nontrivial fermions in this intriguing state of matter.
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Affiliation(s)
- Ziwan Song
- College of Electronic and Optical Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
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11
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Abstract
The Wiedemann-Franz (WF) law is a fundamental result in solid-state physics that relates the thermal and electrical conductivity of a metal. It is derived from the predominant transport mechanism in metals: the motion of quasi-free charge-carrying particles. Here, an equivalent WF relationship is developed for molecular systems in which charge carriers are moving not as free particles but instead hop between redox sites. We derive a concise analytical relationship between the electrical and thermal conductivity generated by electron hopping in molecular systems and find that the linear temperature dependence of their ratio as expressed in the standard WF law is replaced by a linear dependence on the nuclear reorganization energy associated with the electron hopping process. The robustness of the molecular WF relation is confirmed by examining the conductance properties of a paradigmatic molecular junction. This result opens a new way to analyze conductivity in molecular systems, with possible applications advancing the design of molecular technologies that derive their function from electrical and/or thermal conductance.
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Affiliation(s)
- Galen T Craven
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Abraham Nitzan
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
- School of Chemistry , Tel Aviv University , Tel Aviv 69978 , Israel
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12
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Lu J, Xu X, Greenblatt M, Jin R, Tinnemans P, Licciardello S, van Delft MR, Buhot J, Chudzinski P, Hussey NE. Emergence of a real-space symmetry axis in the magnetoresistance of the one-dimensional conductor Li 0.9Mo 6O 17. SCIENCE ADVANCES 2019; 5:eaar8027. [PMID: 31281877 PMCID: PMC6611691 DOI: 10.1126/sciadv.aar8027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
We report on an emerging symmetry axis in the magnetoresistance of bulk single crystals of quasi-one-dimensional Li0.9Mo6O17 below T min = 25 K, the temperature at which the electrical resistivity experiences a minimum. Detailed angle-dependent magnetoresistance sweeps reveal that this symmetry axis is induced by the development of a negative magnetoresistance, which is suppressed only for magnetic fields oriented along the poles of the MoO6 octahedra that form the conducting chains. We show that this unusual negative magnetoresistance is consistent with the melting of dark excitons, composed of previously omitted orbitals within the t 2g manifold that order below T min. The unveiled symmetry axis in directional magnetic fields not only provides evidence for the crystallization of these dark excitons but also sheds new light on the long-standing mystery of the metal-insulator transition in Li0.9Mo6O17.
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Affiliation(s)
- Jianming Lu
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - Xiaofeng Xu
- Advanced Functional Materials Lab and Department of Physics, Changshu Institute of Technology, Changshu 215500, China
| | - M. Greenblatt
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - R. Jin
- Department of Physics and Astronomy, Louisiana State University, 229-B Nicholson Hall, Tower Dr., Baton Rouge, LA 70803-4001, USA
| | - P. Tinnemans
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - S. Licciardello
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - M. R. van Delft
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - J. Buhot
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
| | - P. Chudzinski
- School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast, NI BT7 1NN, UK
| | - N. E. Hussey
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, Nijmegen 6525 ED, Netherlands
- Institute for Molecules and Materials, Radboud University, Nijmegen 6525 AJ, Netherlands
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13
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Liang X, Dai F. Reduction of the Lorenz Number in Copper at Room Temperature due to Strong Inelastic Electron Scattering Brought about by High-Density Dislocations. J Phys Chem Lett 2019; 10:507-512. [PMID: 30645128 DOI: 10.1021/acs.jpclett.8b03544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, heat and charge transport were measured in a series of deformed bulk Cu samples where dislocation density was tuned but dislocation character generally remained unchanged. We observed a notable violation of the Wiedemann-Franz law at room temperature for such a conventional metal. We show that high-density dislocations introduce strong inelastic electron scattering, which relax heat and charge currents to different extents. A reduction of Lorenz number by 15% was observed. We reveal that the contribution from elastic scattering to the incremental thermal resistivity scarcely varies with dislocation density, but the contribution due to inelastic scattering monotonically increases and becomes overwhelmingly dominant for dislocation density above 1.0 × 1015 m-2.
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Affiliation(s)
- Xin Liang
- School of Materials Science and Engineering , Changzhou University , Changzhou , Jiangsu 213164 , China
| | - Feihu Dai
- School of Materials Science and Engineering , Changzhou University , Changzhou , Jiangsu 213164 , China
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14
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Abstract
We report on coupled heat and particle transport measurements through a quantum point contact (QPC) connecting two reservoirs of resonantly interacting, finite temperature Fermi gases. After heating one of them, we observe a particle current flowing from cold to hot. We monitor the temperature evolution of the reservoirs and find that the system evolves after an initial response into a nonequilibrium steady state with finite temperature and chemical potential differences across the QPC. In this state any relaxation in the form of heat and particle currents vanishes. From our measurements we extract the transport coefficients of the QPC and deduce a Lorenz number violating the Wiedemann-Franz law by one order of magnitude, a characteristic persisting even for a wide contact. In contrast, the Seebeck coefficient takes a value close to that expected for a noninteracting Fermi gas and shows a smooth decrease as the atom density close to the QPC is increased beyond the superfluid transition. Our work represents a fermionic analog of the fountain effect observed with superfluid helium and poses challenges for microscopic modeling of the finite temperature dynamics of the unitary Fermi gas.
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15
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Shiraishi Y, Yasumoto N, Imai J, Sakamoto H, Tanaka S, Ichikawa S, Ohtani B, Hirai T. Quantum tunneling injection of hot electrons in Au/TiO 2 plasmonic photocatalysts. NANOSCALE 2017; 9:8349-8361. [PMID: 28594044 DOI: 10.1039/c7nr02310c] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Visible light absorption of plasmonic Au nanoparticles supported on semiconductor TiO2 leads to injection of their photoactivated "hot electrons (ehot-)" into the TiO2 conduction band. This charge separation facilitates several oxidation and reduction reactions. These plasmonic systems, however, suffer from low quantum yields because the Schottky barrier created at the Au-TiO2 interface suppresses ehot- injection. Here we report that Au nanoparticles supported on the anatase particles isolated from Degussa (Evonik) P25 TiO2 promote ehot- injection with much higher efficiency than those supported on other commercially-available TiO2 and catalyze aerobic oxidation with very high quantum yield (7.7% at 550 nm). Photoelectrochemical and spectroscopic analysis revealed that the number of Ti4+ atoms located at the Au-TiO2 interface is the crucial factor. These Ti4+ atoms neutralize the negative charge of the Au particles and create a Schottky barrier with narrower depletion layer. This facilitates efficient ehot- injection by "quantum tunneling" through the Schottky barrier without overbarrier energy. The ehot- injection depends on several factors, and loading of 2 wt% Au particles with 3.5-4 nm diameters at around room temperature exhibits the highest activity of plasmonic photocatalysis.
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Affiliation(s)
- Yasuhiro Shiraishi
- Research Center for Solar Energy Chemistry, and Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
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16
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Mosso N, Drechsler U, Menges F, Nirmalraj P, Karg S, Riel H, Gotsmann B. Heat transport through atomic contacts. NATURE NANOTECHNOLOGY 2017; 12:430-433. [PMID: 28166205 DOI: 10.1038/nnano.2016.302] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 12/28/2016] [Indexed: 06/06/2023]
Abstract
Heat transport and dissipation at the nanoscale severely limit the scaling of high-performance electronic devices and circuits. Metallic atomic junctions serve as model systems to probe electrical and thermal transport down to the atomic level as well as quantum effects that occur in one-dimensional (1D) systems. Whereas charge transport in atomic junctions has been studied intensively in the past two decades, heat transport remains poorly characterized because it requires the combination of a high sensitivity to small heat fluxes and the formation of stable atomic contacts. Here we report heat-transfer measurements through atomic junctions and analyse the thermal conductance of single-atom gold contacts at room temperature. Simultaneous measurements of charge and heat transport reveal the proportionality of electrical and thermal conductance, quantized with the respective conductance quanta. This constitutes a verification of the Wiedemann-Franz law at the atomic scale.
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Affiliation(s)
- Nico Mosso
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Ute Drechsler
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Fabian Menges
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Peter Nirmalraj
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Siegfried Karg
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Heike Riel
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Bernd Gotsmann
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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17
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Huewe F, Steeger A, Kostova K, Burroughs L, Bauer I, Strohriegl P, Dimitrov V, Woodward S, Pflaum J. Low-Cost and Sustainable Organic Thermoelectrics Based on Low-Dimensional Molecular Metals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605682. [PMID: 28195424 DOI: 10.1002/adma.201605682] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/14/2016] [Indexed: 06/06/2023]
Abstract
Thermoelectric generator composed of crystalline radical ion salts: The unipolar charge transport along the molecular stacks facilitates complementary p- and n-type organic thermoelectric materials of high electrical conductivity and of 1D electronic structure. The specific power output of 5 mW cm-2 and the zT > 0.15 below 40 K demonstrate a new field of low-temperature thermoelectric applications unlocked by organic metals.
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Affiliation(s)
- Florian Huewe
- Experimental Physics VI, Julius-Maximilian University of Würzburg, and Bavarian Center for Applied Energy Research (ZAE Bayern e.V.), 97074, Würzburg, Germany
| | - Alexander Steeger
- Experimental Physics VI, Julius-Maximilian University of Würzburg, and Bavarian Center for Applied Energy Research (ZAE Bayern e.V.), 97074, Würzburg, Germany
| | - Kalina Kostova
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria
| | - Laurence Burroughs
- GSK Carbon Neutral Laboratory for Sustainable Chemistry, University of Nottingham, Jubilee Campus, Nottingham, NG7 2GG, UK
| | - Irene Bauer
- Experimental Physics II, University of Bayreuth, 95440, Bayreuth, Germany
| | - Peter Strohriegl
- Macromolecular Chemistry I, University of Bayreuth, 95440, Bayreuth, Germany
| | - Vladimir Dimitrov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria
| | - Simon Woodward
- GSK Carbon Neutral Laboratory for Sustainable Chemistry, University of Nottingham, Jubilee Campus, Nottingham, NG7 2GG, UK
| | - Jens Pflaum
- Experimental Physics VI, Julius-Maximilian University of Würzburg, and Bavarian Center for Applied Energy Research (ZAE Bayern e.V.), 97074, Würzburg, Germany
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18
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Lee S, Hippalgaonkar K, Yang F, Hong J, Ko C, Suh J, Liu K, Wang K, Urban JJ, Zhang X, Dames C, Hartnoll SA, Delaire O, Wu J. Anomalously low electronic thermal conductivity in metallic vanadium dioxide. Science 2017; 355:371-374. [DOI: 10.1126/science.aag0410] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 12/22/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Sangwook Lee
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, South Korea
| | - Kedar Hippalgaonkar
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, 08-03, 138634 Singapore
| | - Fan Yang
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jiawang Hong
- School of Aerospace Engineering and Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Changhyun Ko
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Joonki Suh
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Kai Liu
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
| | - Kevin Wang
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Jeffrey J. Urban
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Xiang Zhang
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
- Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Chris Dames
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
| | - Sean A. Hartnoll
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Olivier Delaire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
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19
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Nonlinear spectra of spinons and holons in short GaAs quantum wires. Nat Commun 2016; 7:12784. [PMID: 27627993 PMCID: PMC5027612 DOI: 10.1038/ncomms12784] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
One-dimensional electronic fluids are peculiar conducting systems, where the fundamental role of interactions leads to exotic, emergent phenomena, such as spin-charge (spinon-holon) separation. The distinct low-energy properties of these 1D metals are successfully described within the theory of linear Luttinger liquids, but the challenging task of describing their high-energy nonlinear properties has long remained elusive. Recently, novel theoretical approaches accounting for nonlinearity have been developed, yet the rich phenomenology that they predict remains barely explored experimentally. Here, we probe the nonlinear spectral characteristics of short GaAs quantum wires by tunnelling spectroscopy, using an advanced device consisting of 6000 wires. We find evidence for the existence of an inverted (spinon) shadow band in the main region of the particle sector, one of the central predictions of the new nonlinear theories. A (holon) band with reduced effective mass is clearly visible in the particle sector at high energies. Recently, theories have emerged that describe the nonlinear high-energy excitations of one-dimensional electronic fluids. Here, the authors report experimental evidence of their existence and behaviour in tunnelling spectra of short GaAs quantum wires.
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20
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Petrović AP, Ansermet D, Chernyshov D, Hoesch M, Salloum D, Gougeon P, Potel M, Boeri L, Panagopoulos C. A disorder-enhanced quasi-one-dimensional superconductor. Nat Commun 2016; 7:12262. [PMID: 27448209 PMCID: PMC4961838 DOI: 10.1038/ncomms12262] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 06/17/2016] [Indexed: 12/01/2022] Open
Abstract
A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2−δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials. Disorder localizes electrons, which is usually detrimental to the onset of superconductivity. Here, Petrović et al. report a disorder-enhanced superconducting instability in quasi-one dimensional Na2-dMo6Se6 and suggest that this effect may originate from an intrinsically screened Coulomb repulsion.
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Affiliation(s)
- A P Petrović
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - D Ansermet
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - D Chernyshov
- Swiss-Norwegian Beamlines, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble Cedex, France
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, Oxfordshire, UK
| | - D Salloum
- Sciences Chimiques, CSM UMR CNRS 6226, Université de Rennes 1, Avenue du Général Leclerc, 35042 Rennes Cedex, France.,Faculty of Science III, Lebanese University, PO Box 826, Kobbeh-Tripoli, Lebanon
| | - P Gougeon
- Sciences Chimiques, CSM UMR CNRS 6226, Université de Rennes 1, Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - M Potel
- Sciences Chimiques, CSM UMR CNRS 6226, Université de Rennes 1, Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - L Boeri
- Institute for Theoretical and Computational Physics, TU Graz, Petersgasse 16, 8010 Graz, Austria
| | - C Panagopoulos
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
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21
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Crossno J, Shi JK, Wang K, Liu X, Harzheim A, Lucas A, Sachdev S, Kim P, Taniguchi T, Watanabe K, Ohki TA, Fong KC. Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene. Science 2016; 351:1058-61. [DOI: 10.1126/science.aad0343] [Citation(s) in RCA: 392] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/06/2016] [Indexed: 11/02/2022]
Affiliation(s)
- Jesse Crossno
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Jing K. Shi
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Ke Wang
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Xiaomeng Liu
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Achim Harzheim
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Andrew Lucas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Subir Sachdev
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Takashi Taniguchi
- National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Thomas A. Ohki
- Quantum Information Processing Group, Raytheon BBN Technologies, Cambridge, MA 02138, USA
| | - Kin Chung Fong
- Quantum Information Processing Group, Raytheon BBN Technologies, Cambridge, MA 02138, USA
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22
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Wu G, Ye XS, Zeng X, Wu B, Clark WG. Investigation of the magnetic dipole field at the atomic scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:015003. [PMID: 26571041 DOI: 10.1088/0953-8984/28/1/015003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report magnetic dipole field investigation at the atomic scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and (7)Li-NMR spectroscopy measurements with an externally applied magnetic field B 0 = 9 T. We find that the magnetic dipole field component ([Formula: see text]) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle [Formula: see text], while the [Formula: see text] maximum is at [Formula: see text] when B 0 is applied perpendicular to b ([Formula: see text]), where [Formula: see text] represents the direction of [Formula: see text]. Further estimation indicates that [Formula: see text] has a maximum value of 0.35 G at B 0 = 9 T. By minimizing the potential magnetic contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the magnetic dipole field component [Formula: see text] is ∼0, the behavior of the electron charge statics is exhibited. This work demonstrates that the magnetic dipole field of the Mo electrons is the dominant source of the local magnetic fields at the Li site, and suggests that the unknown metal-'insulator' crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and magnetic field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material.
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Affiliation(s)
- Guoqing Wu
- College of Physics Science and Technology, Yangzhou University, Yangzhou, Jiangsu 225002, People's Republic of China. Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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23
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Chen X, Weathers A, Carrete J, Mukhopadhyay S, Delaire O, Stewart DA, Mingo N, Girard SN, Ma J, Abernathy DL, Yan J, Sheshka R, Sellan DP, Meng F, Jin S, Zhou J, Shi L. Twisting phonons in complex crystals with quasi-one-dimensional substructures. Nat Commun 2015; 6:6723. [PMID: 25872781 DOI: 10.1038/ncomms7723] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 02/21/2015] [Indexed: 11/09/2022] Open
Abstract
A variety of crystals contain quasi-one-dimensional substructures, which yield distinctive electronic, spintronic, optical and thermoelectric properties. There is a lack of understanding of the lattice dynamics that influences the properties of such complex crystals. Here we employ inelastic neutron scatting measurements and density functional theory calculations to show that numerous low-energy optical vibrational modes exist in higher manganese silicides, an example of such crystals. These optical modes, including unusually low-frequency twisting motions of the Si ladders inside the Mn chimneys, provide a large phase space for scattering acoustic phonons. A hybrid phonon and diffuson model is proposed to explain the low and anisotropic thermal conductivity of higher manganese silicides and to evaluate nanostructuring as an approach to further suppress the thermal conductivity and enhance the thermoelectric energy conversion efficiency. This discovery offers new insights into the structure-property relationships of a broad class of materials with quasi-one-dimensional substructures for various applications.
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Affiliation(s)
- Xi Chen
- Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Annie Weathers
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jesús Carrete
- Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les Nanomatériaux, Commissariat à l'Énergie Atomique Grenoble, Grenoble 38054, France
| | | | - Olivier Delaire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Derek A Stewart
- Cornell Nanoscale Facility, Cornell University, Ithaca, New York 14853, USA
| | - Natalio Mingo
- Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les Nanomatériaux, Commissariat à l'Énergie Atomique Grenoble, Grenoble 38054, France
| | - Steven N Girard
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jie Ma
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Douglas L Abernathy
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Jiaqiang Yan
- 1] Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA [2] Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Raman Sheshka
- Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les Nanomatériaux, Commissariat à l'Énergie Atomique Grenoble, Grenoble 38054, France
| | - Daniel P Sellan
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Fei Meng
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Song Jin
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jianshi Zhou
- Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Li Shi
- 1] Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA [2] Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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24
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Levchenko A. Plasmon decay and thermal transport from spin-charge coupling in generic Luttinger liquids. PHYSICAL REVIEW LETTERS 2014; 113:196401. [PMID: 25415912 DOI: 10.1103/physrevlett.113.196401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 06/04/2023]
Abstract
We discuss the violation of spin-charge separation in generic nonlinear Luttinger liquids and investigate its effect on the relaxation and thermal transport of genuine spin-1/2 electron liquids in ballistic quantum wires. We identify basic scattering processes compatible with the symmetry of the problem and conservation laws that lead to the decay of plasmons into the spin modes. We derive a closed set of coupled kinetic equations for the spin-charge excitations and solve the problem of thermal conductance of interacting electrons for an arbitrary relation between the quantum wire length and spin-charge thermalization length.
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Affiliation(s)
- Alex Levchenko
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
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25
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Cohn JL, Moshfeghyeganeh S, dos Santos CAM, Neumeier JJ. Extreme thermopower anisotropy and interchain transport in the quasi-one-dimensional metal Li0.9Mo6O17. PHYSICAL REVIEW LETTERS 2014; 112:186602. [PMID: 24856710 DOI: 10.1103/physrevlett.112.186602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Indexed: 06/03/2023]
Abstract
Thermopower and electrical resistivity measurements transverse to the conducting chains of the quasi-one-dimensional metal Li0.9Mo6O17 are reported in the temperature range 5≤T≤500 K. For T≥400 K the interchain transport is determined by thermal excitation of charge carriers from a valence band ∼0.14 eV below the Fermi level, giving rise to a large, p-type thermopower that coincides with a small, n-type thermopower along the chains. This dichotomy-semiconductorlike in one direction and metallic in a mutually perpendicular direction-gives rise to substantial transverse thermoelectric effects and a transverse thermoelectric figure of merit among the largest known for a single compound.
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Affiliation(s)
- J L Cohn
- Department of Physics, University of Miami, Coral Gables, Florida 33124, USA
| | - S Moshfeghyeganeh
- Department of Physics, University of Miami, Coral Gables, Florida 33124, USA
| | - C A M dos Santos
- Escola de Engenharia de Lorena - USP, P. O. Box 116, Lorena-SP, 12602-810, Brazil
| | - J J Neumeier
- Department of Physics, Montana State University, Bozeman, Montana 59717, USA
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The Wiedemann-Franz law in the putative one-dimensional metallic phase of PrBa₂Cu₄O₈. Sci Rep 2013; 3:3261. [PMID: 24253025 PMCID: PMC3834867 DOI: 10.1038/srep03261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 10/28/2013] [Indexed: 11/28/2022] Open
Abstract
The nature of the electronic state of a metal depends strongly on its dimensionality. In a system of isolated conducting chains, the Fermi-liquid (quasiparticle) description appropriate for higher dimensions is replaced by the so-called Tomonaga-Luttinger liquid picture characterized by collective excitations of spin and charge. Temperature is often regarded as a viable tuning parameter between states of different dimensionality, but what happens once thermal broadening becomes comparable to the interchain hopping energy remains an unresolved issue, one that is central to many organic and inorganic conductors. Here we use the ratio of the thermal to electrical conductivities to probe the nature of the electronic state in PrBa2Cu4O8 as a function of temperature. We find that despite the interchain transport becoming non-metallic, the charge carriers within the CuO chains appear to retain their quasiparticle nature. This implies that temperature alone cannot induce a crossover from Fermi-liquid to Tomonaga-Luttinger-liquid behaviour in quasi-one-dimensional metals.
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Wang L, Berlijn T, Wang Y, Lin CH, Hirschfeld PJ, Ku W. Effects of disordered Ru substitution in BaFe2As2: possible realization of superdiffusion in real materials. PHYSICAL REVIEW LETTERS 2013; 110:037001. [PMID: 23373944 DOI: 10.1103/physrevlett.110.037001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Indexed: 06/01/2023]
Abstract
An unexpected insensitivity of the Fermi surface to impurity scattering is found in Ru substituted BaFe(2)As(2) from first-principles theory, offering a natural explanation of the unusual resilience of transport and superconductivity to a high level of disordered substitution in this material. This robustness is shown to originate from a coherent interference of correlated on-site and intersite impurity scattering, similar in spirit to the microscopic mechanism of superdiffusion in one dimension. Our result also demonstrates a strong substitution dependence of the Fermi surface and carrier concentration and provides a resolution to current discrepancies in recent photoelectron spectroscopy. These effects offer a natural explanation of the diminishing long-range magnetic, orbital, and superconducting orders with high substitution.
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Affiliation(s)
- Limin Wang
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Podlich T, Klinke M, Nansseu B, Waelsch M, Bienert R, He J, Jin R, Mandrus D, Matzdorf R. Luttinger liquid behaviour of Li0.9Mo6O17 studied by scanning tunnelling microscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:014008. [PMID: 23221173 DOI: 10.1088/0953-8984/25/1/014008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Scanning tunnelling spectroscopy (STS) was used to study the Luttinger liquid behaviour of the purple bronze Li(0.9)Mo(6)O(17) in the temperature range 5 K < T < 300 K. In the entire temperature range the suppression of the density of states at the Fermi energy can be fitted very well by a model describing the tunnelling into a Luttinger liquid at ambient temperature. The power-law exponent extracted from these fits reveals a significant increase above 200 K. It changes from α = 0.6 at low temperature to α = 1.0 at room temperature.
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Affiliation(s)
- T Podlich
- Fachbereich Naturwissenschaften, Universität Kassel, Germany
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Dudy L, Denlinger JD, Allen JW, Wang F, He J, Hitchcock D, Sekiyama A, Suga S. Photoemission spectroscopy and the unusually robust one-dimensional physics of lithium purple bronze. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:014007. [PMID: 23221164 DOI: 10.1088/0953-8984/25/1/014007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Temperature-dependent photoemission spectroscopy in Li(0.9)Mo(6)O(17) contributes to evidence for one-dimensional (1D) physics that is unusually robust. Three generic characteristics of the Luttinger liquid are observed: power law behavior of the k-integrated spectral function down to temperatures just above the superconducting transition, k-resolved lineshapes that show holon and spinon features, and quantum critical (QC) scaling in the lineshapes. Departures of the lineshapes and the scaling from expectations in the Tomonaga-Luttinger model can be partially described by a phenomenological momentum broadening that is presented and discussed. The possibility that some form of 1D physics obtains even down to the superconducting transition temperature is assessed.
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Affiliation(s)
- L Dudy
- Randall Laboratory, University of Michigan, Ann Arbor, 48109, USA.
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Mercure JF, Bangura AF, Xu X, Wakeham N, Carrington A, Walmsley P, Greenblatt M, Hussey NE. Upper critical magnetic field far above the paramagnetic pair-breaking limit of superconducting one-dimensional Li0:9Mo6O17 single crystals. PHYSICAL REVIEW LETTERS 2012; 108:187003. [PMID: 22681108 DOI: 10.1103/physrevlett.108.187003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 09/15/2011] [Indexed: 06/01/2023]
Abstract
The upper critical field H(c2) of purple bronze Li0:9Mo6O17 is found to exhibit a large anisotropy, in quantitative agreement with that expected from the observed electrical resistivity anisotropy. With the field aligned along the most conducting axis, H(c2) increases monotonically with decreasing temperature to a value 5 times larger than the estimated paramagnetic pair-breaking field. Theories for the enhancement of H(c2) invoking spin-orbit scattering or strong-coupling superconductivity are shown to be inadequate in explaining the observed behavior, suggesting that the pairing state in Li0:9Mo6O17 is unconventional and possibly spin triplet.
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Affiliation(s)
- J-F Mercure
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, BS8 1TL, United Kingdom
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Pfau H, Hartmann S, Stockert U, Sun P, Lausberg S, Brando M, Friedemann S, Krellner C, Geibel C, Wirth S, Kirchner S, Abrahams E, Si Q, Steglich F. Thermal and electrical transport across a magnetic quantum critical point. Nature 2012; 484:493-7. [DOI: 10.1038/nature11072] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 03/21/2012] [Indexed: 11/09/2022]
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Cohn JL, White BD, dos Santos CAM, Neumeier JJ. Giant Nernst effect and bipolarity in the quasi-one-dimensional metal Li0.9Mo6O17. PHYSICAL REVIEW LETTERS 2012; 108:056604. [PMID: 22400949 DOI: 10.1103/physrevlett.108.056604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Indexed: 05/31/2023]
Abstract
The Nernst coefficient for the quasi-one-dimensional metal, Li{0.9}Mo{6}O{17}, is found to be among the largest known for metals (ν≃500 μV/KT at T∼20 K), and is enhanced in a broad range of temperature by orders of magnitude over the value expected from Boltzmann theory for carrier diffusion. A comparatively small Seebeck coefficient implies that Li{0.9}Mo{6}O{17} is bipolar with large, partial Seebeck coefficients of opposite sign. A very large thermomagnetic figure of merit, ZT∼0.5, is found at high field in the range T≈35-50 K.
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Affiliation(s)
- J L Cohn
- Department of Physics, University of Miami, Coral Gables, Florida 33124, USA
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