1
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Lee Y, Sur Y, Kim S, Cha J, Hyun J, Lim CY, Hashimoto M, Lu D, Kim Y, Huh S, Kim C, Ideta S, Tanaka K, Kim KH, Kim Y. Coupling Between Electrons and Charge Density Wave Fluctuation and its Possible Role in Superconductivity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2406043. [PMID: 39234922 DOI: 10.1002/advs.202406043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 08/04/2024] [Indexed: 09/06/2024]
Abstract
In most charge density wave (CDW) systems of different material classes, ranging from traditional correlated systems in low-dimension to recent topological systems with Kagome lattice, superconductivity emerges when the system is driven toward the quantum critical point (QCP) of CDW via external parameters of doping and pressure. Despite this rather universal trend, the essential hinge between CDW and superconductivity has not been established yet. Here, the evidence of coupling between electron and CDW fluctuation is reported, based on a temperature- and intercalation-dependent kink in the angle-resolved photoemission spectra of 2H-PdxTaSe2. Kinks are observed only when the system is in the CDW phase, regardless of whether a long- or short-range order is established. Notably, the coupling strength is enhanced upon long-range CDW suppression, albeit the coupling energy scale is reduced. Interestingly, the estimation of the superconducting critical temperature by incorporating the observed coupling characteristics into McMillan's equation yields results closely resembling the known values of the superconducting dome. The results thus highlight a compelling possibility that this new coupling mediates Cooper pairs, which provides new insights into the competing relationship not only for CDW but also for other competing orders.
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Affiliation(s)
- Yeonghoon Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Quantum Technology Institute, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Yeahan Sur
- Department of Physics and Astronomy, Center for Novel States of Complex Materials Research, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sunghun Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Department of Physics, Ajou University, Suwon, 16499, Republic of Korea
| | - Jaehun Cha
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jounghoon Hyun
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chan-Young Lim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Makoto Hashimoto
- Stanford Synchrotron Radiation Light Source, Stanford Linear Accelerator Center, Menlo Park, CA, 94025, USA
| | - Donghui Lu
- Stanford Synchrotron Radiation Light Source, Stanford Linear Accelerator Center, Menlo Park, CA, 94025, USA
| | - Younsik Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Soonsang Huh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Shinichiro Ideta
- Ultra Violet Synchrotron Orbital Radiation, Institute for Molecular Science, Myodaiji, Okazaki, 444-8585, Japan
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
| | - Kiyohisa Tanaka
- Ultra Violet Synchrotron Orbital Radiation, Institute for Molecular Science, Myodaiji, Okazaki, 444-8585, Japan
| | - Kee Hoon Kim
- Department of Physics and Astronomy, Center for Novel States of Complex Materials Research, Seoul National University, Seoul, 08826, Republic of Korea
- Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeongkwan Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
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2
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Bashan N, Tulipman E, Schmalian J, Berg E. Tunable Non-Fermi Liquid Phase from Coupling to Two-Level Systems. PHYSICAL REVIEW LETTERS 2024; 132:236501. [PMID: 38905644 DOI: 10.1103/physrevlett.132.236501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/11/2024] [Accepted: 04/25/2024] [Indexed: 06/23/2024]
Abstract
We study a controlled large-N theory of electrons coupled to dynamical two-level systems (TLSs) via spatially random interactions. Such a physical situation arises when electrons scatter off low-energy excitations in a metallic glass, such as a charge or stripe glass. Our theory is governed by a non-Gaussian saddle point, which maps to the celebrated spin-boson model. By tuning the coupling strength we find that the model crosses over from a Fermi liquid at weak coupling to an extended region of non-Fermi liquid behavior at strong coupling, and realizes a marginal Fermi liquid at the crossover. Our results are valid for generic space dimensions d>1.
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3
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Chen CH, Lan YS, Huang A, Jeng HT. Two-gap topological superconductor LaB 2 with high Tc = 30 K. NANOSCALE HORIZONS 2023; 9:148-155. [PMID: 37938857 DOI: 10.1039/d3nh00249g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Since two gap superconductivity was discovered in MgB2, research on multigap superconductors has attracted increasing attention because of its intriguing fundamental physics. In MgB2, the Mg atom donates two electrons to the borophene layer, resulting in a stronger gap from the σ band and a weaker gap from the π bond. First-principles calculations demonstrate that the two gap anisotropic superconductivity strongly enhances the transition temperature of MgB2 in comparison with that given by the isotropic model. In this work, we report a three-band (B-σ, B-π, and La-d) two-gap superconductor LaB2 with very high Tc = 30 K by solving the fully anisotropic Migdal-Eliashberg equation. Because of the σ and π-d hybridization on the Fermi surface, the electron-phonon coupling constant λ = 1.5 is significantly larger than the λ = 0.7 of MgB2. Our work paves a new route to enhance the electron-phonon coupling strength of multigap superconductors with d orbitals. On the other hand, our analysis reveals that LaB2 belongs to the weak topological semimetal category, leading to a possible topological superconductor with the highest Tc to date. Moreover, upon applying pressure and/or doping, the topology is tunable between weak and strong with Tc varying from 15 to 30 K, opening up a flexible platform for manipulating topological superconductors.
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Affiliation(s)
- Chin-Hsuan Chen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ye-Shun Lan
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Angus Huang
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
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4
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Zhang SS, Chubukov AV. Density of States and Spectral Function of a Superconductor out of a Quantum-Critical Metal. PHYSICAL REVIEW LETTERS 2023; 131:086502. [PMID: 37683155 DOI: 10.1103/physrevlett.131.086502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 07/25/2023] [Indexed: 09/10/2023]
Abstract
We analyze the validity of a quasiparticle description of a superconducting state above a metallic quantum-critical point (QCP). A normal state at a QCP is a non-Fermi liquid with no coherent quasiparticles. A superconducting order gaps out low-energy excitations, except for a sliver of states for non-s-wave gap symmetry, and at a first glance, restores coherent quasiparticle behavior. We argue that this does not necessarily hold as the fermionic self-energy may remain singular above the gap edge. This singularity gives rise to markedly non-BCS behavior of the density of states and to the appearance of a nondispersing mode at the gap edge in the spectral function. We analyze the set of quantum-critical models with an effective dynamical four-fermion interaction V(Ω)∝1/Ω^{γ}, where Ω is a frequency of a boson, which mediates the interaction. We show that coherent quasiparticle behavior in a superconducting state holds for γ<1/2, but breaks down for larger γ. We discuss signatures of quasiparticle breakdown and compare our results with the photoemission data for Bi2201 and Bi2212.
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Affiliation(s)
- Shang-Shun Zhang
- School of Physics and Astronomy and William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Andrey V Chubukov
- School of Physics and Astronomy and William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
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5
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Cai S, Zhao J, Ni N, Guo J, Yang R, Wang P, Han J, Long S, Zhou Y, Wu Q, Qiu X, Xiang T, Cava RJ, Sun L. The breakdown of both strange metal and superconducting states at a pressure-induced quantum critical point in iron-pnictide superconductors. Nat Commun 2023; 14:3116. [PMID: 37253725 DOI: 10.1038/s41467-023-38763-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/11/2023] [Indexed: 06/01/2023] Open
Abstract
Here we report the first observation of the concurrent breakdown of the strange metal (SM) normal state and superconductivity at a pressure-induced quantum critical point in Ca10(Pt4As8)((Fe0.97Pt0.03)2As2)5 superconductor. We find that, upon suppressing the superconducting state, the power exponent (α) changes from 1 to 2, and the slope of the temperature-linear resistivity per FeAs layer (A□) gradually diminishes. At a critical pressure, A□ and superconducting transition temperature (Tc) go to zero concurrently, where a quantum phase transition from a superconducting state with a SM normal state to a non-superconducting Fermi liquid state occurs. Scaling analysis reveals that the change of A□ with Tc obeys the relation of Tc ~ (A□)0.5, similar to what is seen in other chemically doped unconventional superconductors. These results suggest that there is a simple but powerful organizational principle of connecting the SM normal state with the high-Tc superconductivity.
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Affiliation(s)
- Shu Cai
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Jinyu Zhao
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Ni Ni
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095, USA
| | - Jing Guo
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China
| | - Run Yang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Pengyu Wang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Jinyu Han
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Sijin Long
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Yazhou Zhou
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Qi Wu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Xianggang Qiu
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China
| | - Tao Xiang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
| | - Liling Sun
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
- University of Chinese Academy of Sciences, 100190, Beijing, China.
- Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China.
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6
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Liu Y, Huang H, Yuan J, Zhang Y, Feng H, Chen N, Li Y, Teng J, Jin K, Xue D, Su Y. Upper limit of the transition temperature of superconducting materials. PATTERNS (NEW YORK, N.Y.) 2022; 3:100609. [PMID: 36419453 PMCID: PMC9676523 DOI: 10.1016/j.patter.2022.100609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 08/05/2022] [Accepted: 09/21/2022] [Indexed: 11/12/2022]
Abstract
Why are the transition temperatures (T c) of superconducting materials so different? The answer to this question is not only of great significance in revealing the mechanism of high-T c superconductivity but also can be used as a guide for the design of new superconductors. However, so far, it is still challenging to identify the governing factors affecting the T c. In this work, with the aid of machine learning and first-principles calculations, we found a close relevance between the upper limit of the T c and the energy-level distribution of valence electrons. It implies that some additional inter-orbital electron-electron interaction should be considered in the interpretation of high-T c superconductivity.
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Affiliation(s)
- Yang Liu
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Haiyou Huang
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Jie Yuan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yan Zhang
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongyuan Feng
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
| | - Ning Chen
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yang Li
- Department of Engineering Science and Materials, University of Puerto Rico, Mayaguez, PR 00681-9000, USA
| | - Jiao Teng
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Kui Jin
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dezhen Xue
- State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China
| | - Yanjing Su
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China
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7
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Abstract
Interactions between quasiparticles are of fundamental importance and ultimately determine the macroscopic properties of quantum matter. A famous example is the phenomenon of superconductivity, which arises from attractive electron-electron interactions that are mediated by phonons or even other more exotic fluctuations in the material. Here we introduce mobile exciton impurities into a two-dimensional electron gas and investigate the interactions between the resulting Fermi polaron quasiparticles. We employ multi-dimensional coherent spectroscopy on monolayer WS2, which provides an ideal platform for determining the nature of polaron-polaron interactions due to the underlying trion fine structure and the valley specific optical selection rules. At low electron doping densities, we find that the dominant interactions are between polaron states that are dressed by the same Fermi sea. In the absence of bound polaron pairs (bipolarons), we show using a minimal microscopic model that these interactions originate from a phase-space filling effect, where excitons compete for the same electrons. We furthermore reveal the existence of a bipolaron bound state with remarkably large binding energy, involving excitons in different valleys cooperatively bound to the same electron. Our work lays the foundation for probing and understanding strong electron correlation effects in two-dimensional layered structures such as moiré superlattices. Here, the authors investigate the interactions between Fermi polarons in monolayer WS2 by multi-dimensional coherent spectroscopy, and find that, at low electron doping densities, the dominant interactions are between polaron states that are dressed by the same Fermi sea. They also observe a bipolaron bound state with large binding energy, involving excitons in different valleys cooperatively bound to the same electron.
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8
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Abstract
In traditional metals, the temperature (
T
) dependence of electrical resistivity vanishes at low or high
T
, albeit for different reasons. Here, we review a class of materials, known as “strange” metals, that can violate both of these principles. In strange metals, the change in slope of the resistivity as the mean free path drops below the lattice constant, or as
T
→ 0, can be imperceptible, suggesting continuity between the charge carriers at low and high
T
. We focus on transport and spectroscopic data on candidate strange metals in an effort to isolate and identify a unifying physical principle. Special attention is paid to quantum criticality, Planckian dissipation, Mottness, and whether a new gauge principle is needed to account for the nonlocal transport seen in these materials.
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Affiliation(s)
- Philip W. Phillips
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois, Urbana, IL 61801, USA
| | - Nigel E. Hussey
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, Netherlands
| | - Peter Abbamonte
- Department of Physics, University of Illinois, Urbana, IL 61801, USA
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9
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Hussey NE, Duffy C. Strange metallicity and high-T c superconductivity: quantifying the paradigm. Sci Bull (Beijing) 2022; 67:985-987. [PMID: 36546252 DOI: 10.1016/j.scib.2022.03.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Nigel E Hussey
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK; HFML-FELIX and Institute for Molecules and Materials, Radboud University, Nijmegen 6525ED, Netherlands.
| | - Caitlin Duffy
- HFML-FELIX and Institute for Molecules and Materials, Radboud University, Nijmegen 6525ED, Netherlands
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10
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Orgiani P, Galdi A, Schlom DG, Maritato L. Normal-State Transport Properties of Infinite-Layer Sr 1-xLa xCuO 2 Electron-Doped Cuprates in Optimal- and Over-Doped Regimes. NANOMATERIALS 2022; 12:nano12101709. [PMID: 35630928 PMCID: PMC9146696 DOI: 10.3390/nano12101709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/08/2022] [Accepted: 05/13/2022] [Indexed: 12/03/2022]
Abstract
Transport properties of electron-doped cuprate Sr1−xLaxCuO2 thin films have been investigated as a function of doping. In particular, optimal- and over-doped samples were obtained by tuning the Sr:La stoichiometric ratio. Optimal-doped samples show a non-Fermi liquid behavior characterized by linear dependence of the resistivity from room temperature down to intermediate temperature (about 150–170 K). However, by approaching temperatures in the superconducting transition, a Fermi-liquid behavior-characterized by a T2-scaling law-was observed. Once established, the transition from a linear-T to a quadratic-T2 behavior was successfully traced back in over-doped samples, even occurring at lower temperatures. In addition, the over-doped samples show a crossover to a linear-T to a logarithmic dependence at high temperatures compatible with anti-ferromagnetic spin fluctuations dominating the normal state properties of electron-doped cuprates.
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Affiliation(s)
- Pasquale Orgiani
- CNR-IOM, TASC Laboratory in Area Science Park, 34139 Trieste, Italy
- Correspondence:
| | - Alice Galdi
- Dipartimento di Ingegneria Industriale, Università degli Studi di Salerno, 84084 Fisciano, Italy; (A.G.); (L.M.)
| | - Darrell G. Schlom
- Department of Material Science and Engineering, Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA;
| | - Luigi Maritato
- Dipartimento di Ingegneria Industriale, Università degli Studi di Salerno, 84084 Fisciano, Italy; (A.G.); (L.M.)
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11
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Scaling of the strange-metal scattering in unconventional superconductors. Nature 2022; 602:431-436. [PMID: 35173341 DOI: 10.1038/s41586-021-04305-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/29/2021] [Indexed: 11/08/2022]
Abstract
Marked evolution of properties with minute changes in the doping level is a hallmark of the complex chemistry that governs copper oxide superconductivity as manifested in the celebrated superconducting domes and quantum criticality taking place at precise compositions1-4. The strange-metal state, in which the resistivity varies linearly with temperature, has emerged as a central feature in the normal state of copper oxide superconductors5-9. The ubiquity of this behaviour signals an intimate link between the scattering mechanism and superconductivity10-12. However, a clear quantitative picture of the correlation has been lacking. Here we report the observation of precise quantitative scaling laws among the superconducting transition temperature (Tc), the linear-in-T scattering coefficient (A1) and the doping level (x) in electron-doped copper oxide La2-xCexCuO4 (LCCO). High-resolution characterization of epitaxial composition-spread films, which encompass the entire overdoped range of LCCO, has enabled us to systematically map its structural and transport properties with unprecedented accuracy and with increments of Δx = 0.0015. We have uncovered the relations Tc ~ (xc - x)0.5 ~ (A1□)0.5, where xc is the critical doping in which superconductivity disappears and A1□ is the coefficient of the linear resistivity per CuO2 plane. The striking similarity of the Tc versus A1□ relation among copper oxides, iron-based and organic superconductors may be an indication of a common mechanism of the strange-metal behaviour and unconventional superconductivity in these systems.
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12
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Signatures of a strange metal in a bosonic system. Nature 2022; 601:205-210. [PMID: 35022592 DOI: 10.1038/s41586-021-04239-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 11/09/2021] [Indexed: 11/08/2022]
Abstract
Fermi liquid theory forms the basis for our understanding of the majority of metals: their resistivity arises from the scattering of well defined quasiparticles at a rate where, in the low-temperature limit, the inverse of the characteristic time scale is proportional to the square of the temperature. However, various quantum materials1-15-notably high-temperature superconductors1-10-exhibit strange-metallic behaviour with a linear scattering rate in temperature, deviating from this central paradigm. Here we show the unexpected signatures of strange metallicity in a bosonic system for which the quasiparticle concept does not apply. Our nanopatterned YBa2Cu3O7-δ (YBCO) film arrays reveal linear-in-temperature and linear-in-magnetic field resistance over extended temperature and magnetic field ranges. Notably, below the onset temperature at which Cooper pairs form, the low-field magnetoresistance oscillates with a period dictated by the superconducting flux quantum, h/2e (e, electron charge; h, Planck's constant). Simultaneously, the Hall coefficient drops and vanishes within the measurement resolution with decreasing temperature, indicating that Cooper pairs instead of single electrons dominate the transport process. Moreover, the characteristic time scale τ in this bosonic system follows a scale-invariant relation without an intrinsic energy scale: ħ/τ ≈ a(kBT + γμBB), where ħ is the reduced Planck's constant, a is of order unity7,8,11,12, kB is Boltzmann's constant, T is temperature, μB is the Bohr magneton and γ ≈ 2. By extending the reach of strange-metal phenomenology to a bosonic system, our results suggest that there is a fundamental principle governing their transport that transcends particle statistics.
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13
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Else DV, Senthil T. Strange Metals as Ersatz Fermi Liquids. PHYSICAL REVIEW LETTERS 2021; 127:086601. [PMID: 34477402 DOI: 10.1103/physrevlett.127.086601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
A long-standing mystery of fundamental importance in correlated electron physics is to understand strange non-Fermi liquid metals that are seen in diverse quantum materials. A striking experimental feature of these metals is a resistivity that is linear in temperature (T). In this Letter we ask what it takes to obtain such non-Fermi liquid physics down to zero temperature in a translation invariant metal. If in addition the full frequency (ω) dependent conductivity satisfies ω/T scaling, we argue that the T-linear resistivity must come from the intrinsic physics of the low energy fixed point. Combining with earlier arguments that compressible translation invariant metals are "ersatz Fermi liquids" with an infinite number of emergent conserved quantities, we obtain powerful and practical conclusions. We show that there is necessarily a diverging susceptibility for an operator that is odd under inversion and time reversal symmetries, and has zero crystal momentum. We discuss a few other experimental consequences of our arguments, as well as potential loopholes, which necessarily imply other exotic phenomena.
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Affiliation(s)
- Dominic V Else
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - T Senthil
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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14
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Surface localized magnetism in transition metal doped alumina. Sci Rep 2021; 11:6410. [PMID: 33742044 PMCID: PMC7979734 DOI: 10.1038/s41598-021-85791-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/02/2021] [Indexed: 11/23/2022] Open
Abstract
Alumina is a structural ceramic that finds many uses in a broad range of applications. It is widely employed in the aerospace and biomedical sectors due to its stability at high temperatures and in harsh chemical environments. Here, we show that magnetism can be induced at alumina surfaces by doping with 3d transition metals. We analyze the electronic structure, spin magnetic moments, and spin density of \documentclass[12pt]{minimal}
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\begin{document}$$_{3}$$\end{document}3 as a function of both dopant species (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) and depth using first principles calculations. Our results show that all dopants, with the exception of Sc, produce magnetic moments that are concentrated to the surface of alumina with varying degrees of delocalization. It is seen that all of the dopants are at least meta-stable on the surface and must overcome an energy barrier of 0.19–1.14 eV in order to diffuse from the surface into the bulk. As a result of judiciously doping with select 3d transition metals the surface of alumina can be made magnetic. This could lead to novel applications in data storage, catalysis, and biomedical engineering through an added surface functionality.
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15
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Gao L, Chen X, Lyu X, Ji G, Chen Z, Zhu M, Cao X, Li C, Ji A, Cao Z, Lu N. Tracing the ionic evolution during ILG induced phase transformation in strontium cobaltite thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:104004. [PMID: 33570048 DOI: 10.1088/1361-648x/abd1b7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ionic liquid gating (ILG) that drives the ions incorporate into or extract from the crystal lattice, has emerged as a new pathway to design materials. Although many intriguing emergent phenomena, novel physical properties and functionalities have been obtained, the gating mechanism governing the ion and charge transport remains unexplored. Here, by using the model system of brownmillerite SrCoO2.5 and the corresponding electric-field controlled tri-state phase transformation among the pristine SrCoO2.5, hydrogenated HSrCoO2.5 and oxidized perovskite SrCoO3-δ through the dual ion switch, the ionic diffusion and electronic transport processes were carefully investigated. Through controlling gating experiment by design, we find out that the collaborative interaction between charge transport and ion diffusion plays an essential role to prompt the hydrogen or oxygen ions incorporate into the crystal lattice of SrCoO2.5, and therefore leading to formation of new phases. At region closer to the electrode, the electron can shuttle more readily in (out) the material, correspondingly the incorporation of hydrogen (oxygen) ions and phase transformation is largely affiliated. With the compensated charge of electron as well as the reaction front gradually moving away from the electrode, the new phases would be developed successively across the entire thin film. This result unveils the underlying mechanism in the electric-field control of ionic incorporation and extraction, and therefore provides important strategy to achieve high efficient design of material functionalities in complex oxide materials.
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Affiliation(s)
- Lei Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xiaokun Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xiangyu Lyu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Guiping Ji
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Zhanfen Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Center for Optoelectronics Materials and Devices & Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Mingtong Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xun Cao
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Dingxi Road 1295, Changning, Shanghai 200050, People's Republic of China
| | - Chaorong Li
- Center for Optoelectronics Materials and Devices & Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Ailing Ji
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Zexian Cao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Nianpeng Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
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16
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Kang K, Kim WJ, Kim D, Kim S, Ji B, Keum DH, Cho S, Kim YM, Lebègue S, Yang H. Lifshitz Transition and Non-Fermi Liquid Behavior in Highly Doped Semimetals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005742. [PMID: 33241603 DOI: 10.1002/adma.202005742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/19/2020] [Indexed: 06/11/2023]
Abstract
The classical Fermi liquid theory and Drude model have provided fundamental ways to understand the resistivity of most metals. The violation of the classical theory, known as non-Fermi liquid (NFL) transport, appears in certain metals, including topological semimetals, but quantitative understanding of the NFL behavior has not yet been established. In particular, the determination of the non-quadratic temperature exponent in the resistivity, a sign of NFL behavior, remains a puzzling issue. Here, a physical model to quantitatively explain the Lifshitz transition and NFL behavior in highly doped (a carrier density of ≈1022 cm-3 ) monoclinic Nb2 Se3 is reported. Hall and magnetoresistance measurements, the two-band Drude model, and first-principles calculations demonstrate an apparent chemical potential shift by temperature in monoclinic Nb2 Se3 , which induces a Lifshitz transition and NFL behavior in the material. Accordingly, the non-quadratic temperature exponent in the resistivity can be quantitatively determined by the chemical potential shift under the framework of Fermi liquid theory. This model provides a new experimental insight for nontrivial transport with NFL behavior or sign inversion of Seebeck coefficients in emerging materials.
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Affiliation(s)
- Kyungrok Kang
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Won June Kim
- Department of Biology and Chemistry, Changwon National University, Changwon, 51140, Korea
| | - Dohyun Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sera Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Byungdo Ji
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dong Hoon Keum
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 16419, Korea
| | - Suyeon Cho
- Division of Chemical Engineering and Materials Science, Ewha Womans University, Seoul, 03760, Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sébastien Lebègue
- Laboratoire de Physique et Chimie Théoriques (LPCT, UMR CNRS 7019), Université de Lorraine, Vandoeuvre-lès-, Nancy, 54506, France
| | - Heejun Yang
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
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17
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A selective control of volatile and non-volatile superconductivity in an insulating copper oxide via ionic liquid gating. Sci Bull (Beijing) 2020; 65:1607-1613. [PMID: 36659036 DOI: 10.1016/j.scib.2020.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/24/2020] [Accepted: 05/14/2020] [Indexed: 01/21/2023]
Abstract
Manipulating the superconducting states of high transition temperature (high-Tc) cuprate superconductors in an efficient and reliable way is of great importance for their applications in next-generation electronics. Here, employing ionic liquid gating, a selective control of volatile and non-volatile superconductivity is achieved in pristine insulating Pr2CuO4±δ (PCO) films, based on two distinct mechanisms. Firstly, with positive electric fields, the film can be reversibly switched between superconducting and non-superconducting states, attributed to the carrier doping effect. Secondly, the film becomes more resistive by applying negative bias voltage up to - 4 V, but strikingly, a non-volatile superconductivity is achieved once the gate voltage is removed. Such phenomenon represents a distinctive route of manipulating superconductivity in PCO, resulting from the doping healing of oxygen vacancies in copper-oxygen planes as unravelled by high-resolution scanning transmission electron microscope and in situ X-ray diffraction experiments. The effective manipulation of volatile/non-volatile superconductivity in the same parent cuprate brings more functionalities to superconducting electronics, as well as supplies flexible samples for investigating the nature of quantum phase transitions in high-Tc superconductors.
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18
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Rodrigues JNB, Wagner LK. Identifying materials with charge-spin physics using charge-spin susceptibility computed from first principles. J Chem Phys 2020; 153:074105. [PMID: 32828081 DOI: 10.1063/1.5144911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a quantity termed charge-spin susceptibility, which measures the charge response to spin degrees of freedom in strongly correlated materials. This quantity is simple to evaluate using both standard density functional theory and many-body electronic structure techniques, enabling comparison between different levels of theory. A benchmark on 28 layered magnetic materials shows that large values of charge-spin susceptibility correlate with unconventional ground states such as disordered magnets and unconventional superconductivity.
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Affiliation(s)
- J N B Rodrigues
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Lucas K Wagner
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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19
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Sarkar T, Wei DS, Zhang J, Poniatowski NR, Mandal PR, Kapitulnik A, Greene RL. Ferromagnetic order beyond the superconducting dome in a cuprate superconductor. Science 2020; 368:532-534. [PMID: 32355032 DOI: 10.1126/science.aax1581] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 10/23/2019] [Accepted: 03/25/2020] [Indexed: 11/02/2022]
Abstract
According to conventional wisdom, the extraordinary properties of the cuprate high-temperature superconductors arise from doping a strongly correlated antiferromagnetic insulator. The highly overdoped cuprates-whose doping lies beyond the dome of superconductivity-are considered to be conventional Fermi liquid metals. We report the emergence of itinerant ferromagnetic order below 4 kelvin for doping beyond the superconducting dome in thin films of electron-doped La2- x Ce x CuO4 (LCCO). The existence of this ferromagnetic order is evidenced by negative, anisotropic, and hysteretic magnetoresistance, hysteretic magnetization, and the polar Kerr effect, all of which are standard signatures of itinerant ferromagnetism in metals. This surprising result suggests that the overdoped cuprates are strongly influenced by electron correlations.
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Affiliation(s)
- Tarapada Sarkar
- Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - D S Wei
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - J Zhang
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - N R Poniatowski
- Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - P R Mandal
- Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - A Kapitulnik
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
- Stanford Institute for Materials and Energy Sciences (SIMES), SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Richard L Greene
- Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, MD 20742, USA.
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20
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Šimkovic F, LeBlanc JPF, Kim AJ, Deng Y, Prokof'ev NV, Svistunov BV, Kozik E. Extended Crossover from a Fermi Liquid to a Quasiantiferromagnet in the Half-Filled 2D Hubbard Model. PHYSICAL REVIEW LETTERS 2020; 124:017003. [PMID: 31976700 DOI: 10.1103/physrevlett.124.017003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 10/08/2019] [Indexed: 06/10/2023]
Abstract
The ground state of the Hubbard model with nearest-neighbor hopping on the square lattice at half filling is known to be that of an antiferromagnetic (AFM) band insulator for any on-site repulsion. At finite temperature, the absence of long-range order makes the question of how the interaction-driven insulator is realized nontrivial. We address this problem with controlled accuracy in the thermodynamic limit using self-energy diagrammatic determinant Monte Carlo and dynamical cluster approximation methods and show that development of long-range AFM correlations drives an extended crossover from Fermi liquid to insulating behavior in the parameter regime that precludes a metal-to-insulator transition. The intermediate crossover state is best described as a non-Fermi liquid with a partially gapped Fermi surface.
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Affiliation(s)
- Fedor Šimkovic
- Department of Physics, Kings College London, Strand, London WC2R 2LS, United Kingdom
| | - J P F LeBlanc
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7, Canada
| | - Aaram J Kim
- Department of Physics, Kings College London, Strand, London WC2R 2LS, United Kingdom
| | - Youjin Deng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - N V Prokof'ev
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
- National Research Center "Kurchatov Institute," 123182 Moscow, Russia
| | - B V Svistunov
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
- National Research Center "Kurchatov Institute," 123182 Moscow, Russia
- Wilczek Quantum Center, School of Physics and Astronomy and T. D. Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Evgeny Kozik
- Department of Physics, Kings College London, Strand, London WC2R 2LS, United Kingdom
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21
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He G, Wei Z, Feng Z, Yu X, Zhu B, Liu L, Jin K, Yuan J, Huan Q. Combinatorial laser molecular beam epitaxy system integrated with specialized low-temperature scanning tunneling microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:013904. [PMID: 32012528 DOI: 10.1063/1.5119686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
We present a newly developed facility comprising a combinatorial laser molecular beam epitaxy system and an in situ scanning tunneling microscope (STM). This facility aims at accelerating the materials research in a highly efficient way by advanced high-throughput film synthesis techniques and subsequent fast characterization of surface morphology and electronic states. Compared with uniform films deposited by conventional methods, the so-called combinatorial thin films will be beneficial in determining the accurate phase diagrams of different materials due to the improved control of parameters such as chemical substitution and sample thickness resulting from a rotary-mask method. A specially designed STM working under low-temperature and ultrahigh vacuum conditions is optimized for the characterization of combinatorial thin films in an XY coarse motion range of 15 mm × 15 mm with submicrometer location precision. The overall configuration and some key aspects such as the sample holder design, scanner head, and sample/tip/target transfer mechanism are described in detail. The performance of the device is demonstrated by synthesizing high-quality superconducting FeSe thin films with gradient thickness and imaging surfaces of highly oriented pyrolytic graphite, Au (111), Bi2Sr2CaCu2O8+δ (BSCCO), and FeSe. In addition, we also have obtained clean noise spectra of tunneling junctions and the superconducting energy gap of BSCCO. The successful manufacturing of such a facility opens a new window for the next generation equipment designed for experimental materials research.
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Affiliation(s)
- Ge He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongxu Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongpei Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaodong Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Beiyi Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Li Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kui Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Yuan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Huan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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22
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Rafique M, Feng Z, Lin Z, Wei X, Liao M, Zhang D, Jin K, Xue QK. Ionic Liquid Gating Induced Protonation of Electron-Doped Cuprate Superconductors. NANO LETTERS 2019; 19:7775-7780. [PMID: 31664842 DOI: 10.1021/acs.nanolett.9b02776] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ion injection controlled by electric field has attracted growing attention due to its tunability over bulk-like materials. Here, we achieve protonation of an electron-doped high-temperature superconductor, La2-xCexCuO4, by gating in the electrochemical regime of the ionic liquid. Such a process induces a superconductor-insulator transition together with the crossing of the Fermi surface reconstruction point. Applying negative voltages not only can reverse the protonation process but also recovers superconductivity in samples deteriorated by moisture in the ambient. Our work extends the application of electric-field-induced protonation into high-temperature cuprate superconductors.
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Affiliation(s)
- Mohsin Rafique
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics , Tsinghua University , Beijing 100084 , China
| | - Zhongpei Feng
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Zefeng Lin
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xinjian Wei
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Menghan Liao
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics , Tsinghua University , Beijing 100084 , China
| | - Ding Zhang
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics , Tsinghua University , Beijing 100084 , China
- Beijing Academy of Quantum Information Sciences , Beijing 100193 , China
- Frontier Science Center for Quantum Information , Beijing 100084 , China
| | - Kui Jin
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Qi-Kun Xue
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics , Tsinghua University , Beijing 100084 , China
- Beijing Academy of Quantum Information Sciences , Beijing 100193 , China
- Frontier Science Center for Quantum Information , Beijing 100084 , China
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23
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Wei TT, Chen L, Fu HH, Shi YL, Hou J, Yu F, Ye J, Li H, Fan C, Chen D, Dai B. Synthesis and formation mechanism of monodisperse Mn-Co-Ni-O spinel nanocrystallines. ADV POWDER TECHNOL 2019. [DOI: 10.1016/j.apt.2019.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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24
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Sarkar T, Mandal PR, Poniatowski NR, Chan MK, Greene RL. Correlation between scale-invariant normal-state resistivity and superconductivity in an electron-doped cuprate. SCIENCE ADVANCES 2019; 5:eaav6753. [PMID: 31114800 PMCID: PMC6524976 DOI: 10.1126/sciadv.aav6753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
An understanding of the normal state in the high-temperature superconducting cuprates is crucial to the ultimate understanding of the long-standing problem of the origin of the superconductivity itself. This so-called "strange metal" state is thought to be associated with a quantum critical point (QCP) hidden beneath the superconductivity. In electron-doped cuprates-in contrast to hole-doped cuprates-it is possible to access the normal state at very low temperatures and low magnetic fields to study this putative QCP and to probe the T ➔ 0 K state of these materials. We report measurements of the low-temperature normal-state magnetoresistance (MR) of the n-type cuprate system La2-x Ce x CuO4 and find that it is characterized by a linear-in-field behavior, which follows a scaling relation with applied field and temperature, for doping (x) above the putative QCP (x = 0.14). The magnitude of the unconventional linear MR decreases as T c decreases and goes to zero at the end of the superconducting dome (x ~ 0.175) above which a conventional quadratic MR is found. These results show that there is a strong correlation between the quantum critical excitations of the strange metal state and the high-T c superconductivity.
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Affiliation(s)
- Tarapada Sarkar
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - P. R. Mandal
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - N. R. Poniatowski
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - M. K. Chan
- The National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Richard L. Greene
- Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, MD 20742, USA
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25
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Abstract
In the physics of condensed matter, quantum critical phenomena and unconventional superconductivity are two major themes. In electron-doped cuprates, the low critical field (HC2) allows one to study the putative quantum critical point (QCP) at low temperature and to understand its connection to the long-standing problem of the origin of the high-TC superconductivity. Here we present measurements of the low-temperature normal-state thermopower (S) of the electron-doped cuprate superconductor La2-x Ce x CuO4 (LCCO) from x = 0.11-0.19. We observe quantum critical [Formula: see text] versus [Formula: see text] behavior over an unexpectedly wide doping range x = 0.15-0.17 above the QCP (x = 0.14), with a slope that scales monotonically with the superconducting transition temperature (TC with H = 0). The presence of quantum criticality over a wide doping range provides a window on the criticality. The thermopower behavior also suggests that the critical fluctuations are linked with TC Above the superconductivity dome, at x = 0.19, a conventional Fermi-liquid [Formula: see text] behavior is found for [Formula: see text] 40 K.
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26
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Fermi surface reconstruction in electron-doped cuprates without antiferromagnetic long-range order. Proc Natl Acad Sci U S A 2019; 116:3449-3453. [PMID: 30808739 DOI: 10.1073/pnas.1816121116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fermi surface (FS) topology is a fundamental property of metals and superconductors. In electron-doped cuprate Nd2-x Ce x CuO4 (NCCO), an unexpected FS reconstruction has been observed in optimal- and overdoped regime (x = 0.15-0.17) by quantum oscillation measurements (QOM). This is all the more puzzling because neutron scattering suggests that the antiferromagnetic (AFM) long-range order, which is believed to reconstruct the FS, vanishes before x = 0.14. To reconcile the conflict, a widely discussed external magnetic-field-induced AFM long-range order in QOM explains the FS reconstruction as an extrinsic property. Here, we report angle-resolved photoemission (ARPES) evidence of FS reconstruction in optimal- and overdoped NCCO. The observed FSs are in quantitative agreement with QOM, suggesting an intrinsic FS reconstruction without field. This reconstructed FS, despite its importance as a basis to understand electron-doped cuprates, cannot be explained under the traditional scheme. Furthermore, the energy gap of the reconstruction decreases rapidly near x = 0.17 like an order parameter, echoing the quantum critical doping in transport. The totality of the data points to a mysterious order between x = 0.14 and 0.17, whose appearance favors the FS reconstruction and disappearance defines the quantum critical doping. A recent topological proposal provides an ansatz for its origin.
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27
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Bhattacharjee S, Chaudhury R. Effective Interaction in a Non-Fermi Liquid Conductor and Spin Correlations in Under-Doped Cuprates. JOURNAL OF LOW TEMPERATURE PHYSICS 2018; 193:21-38. [DOI: 10.1007/s10909-018-1998-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 06/15/2018] [Indexed: 07/19/2023]
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28
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Tracking aluminium impurities in single crystals of the heavy-fermion superconductor UBe 13. Sci Rep 2018; 8:10654. [PMID: 30006638 PMCID: PMC6045676 DOI: 10.1038/s41598-018-28991-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/02/2018] [Indexed: 12/02/2022] Open
Abstract
The influence of Al incorporation on the heavy fermion superconductor UBe13 was investigated to explain the sample dependence of physical properties. Clear evidence for incorporated Al in flux-grown UBe13 single crystals is presented by results from X-ray diffraction, nuclear magnetic resonance and X-ray spectroscopy. The increase of the lattice parameter and the concomitant change of the superconducting properties are caused by substitution of Be in the compound by 1–2 at.% Al. The minute amounts of Al in the structure were located by atomic resolution transmission electron microscopy. Specific heat measurements reveal the strong influence of incorporated Al on the physical properties of UBe13. Upon long-term annealing, Al incorporated in single crystals can leave the structure, restoring properties of Al-free polycrystalline UBe13.
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29
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Shaginyan VR, Stephanovich VA, Msezane AZ, Japaridze GS, Popov KG. The influence of topological phase transition on the superfluid density of overdoped copper oxides. Phys Chem Chem Phys 2018; 19:21964-21969. [PMID: 28805230 DOI: 10.1039/c7cp02720f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show that a quantum phase transition, generating flat bands and altering Fermi surface topology, is a primary reason for the exotic behavior of the overdoped high-temperature superconductors represented by La2-xSrxCuO4, whose superconductivity features differ from what is predicted by the classical Bardeen-Cooper-Schrieffer theory. This observation can open avenues for chemical preparation of high-Tc materials. We demonstrate that (1) at temperature T = 0, the superfluid density ns turns out to be considerably smaller than the total electron density; (2) the critical temperature Tc is controlled by ns rather than by doping, and is a linear function of the ns; (3) at T > Tc the resistivity ρ(T) varies linearly with temperature, ρ(T) ∝ αT, where α diminishes with Tc → 0, whereas in the normal (non superconducting) region induced by overdoping, Tc = 0, and ρ(T) ∝ T2. Our results are in good agreement with recent experimental observations.
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Affiliation(s)
- V R Shaginyan
- Petersburg Nuclear Physics Institute, NRC "Kurchatov Institute", Gatchina, 188300, Russia.
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30
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Reemergence of high-T c superconductivity in the (Li 1-xFe x )OHFe 1-ySe under high pressure. Nat Commun 2018; 9:380. [PMID: 29371605 PMCID: PMC5785538 DOI: 10.1038/s41467-018-02843-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/03/2018] [Indexed: 11/09/2022] Open
Abstract
In order to elucidate pressure-induced second superconducting phase (SC-II) in A x Fe2-ySe2 (A = K, Rb, Cs, and Tl) having an intrinsic phase separation, we perform a detailed high-pressure magnetotransport study on the isoelectronic, phase-pure (Li1-xFe x )OHFe1-ySe single crystals. Here we show that its ambient-pressure superconducting phase (SC-I) with a critical temperature Tc ≈ 40 K is suppressed gradually to below 2 K and an SC-II phase emerges above Pc ≈ 5 GPa with Tc increasing progressively to above 50 K up to 12.5 GPa. Our high-precision resistivity data uncover a sharp transition of the normal state from Fermi liquid for SC-I to non-Fermi liquid for SC-II phase. In addition, the reemergence of high-Tc SC-II is found to accompany with a concurrent enhancement of electron carrier density. Without structural transition below 10 GPa, the observed SC-II with enhanced carrier density should be ascribed to an electronic origin presumably associated with pressure-induced Fermi surface reconstruction.
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Paglione J, Tanatar MA, Reid JP, Shakeripour H, Petrovic C, Taillefer L. Quantum Critical Quasiparticle Scattering within the Superconducting State of CeCoIn_{5}. PHYSICAL REVIEW LETTERS 2016; 117:016601. [PMID: 27419578 DOI: 10.1103/physrevlett.117.016601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 06/06/2023]
Abstract
The thermal conductivity κ of the heavy-fermion metal CeCoIn_{5} was measured in the normal and superconducting states as a function of temperature T and magnetic field H, for a current and field parallel to the [100] direction. Inside the superconducting state, when the field is lower than the upper critical field H_{c2}, κ/T is found to increase as T→0, just as in a metal and in contrast to the behavior of all known superconductors. This is due to unpaired electrons on part of the Fermi surface, which dominate the transport above a certain field. The evolution of κ/T with field reveals that the electron-electron scattering (or transport mass m^{⋆}) of those unpaired electrons diverges as H→H_{c2} from below, in the same way that it does in the normal state as H→H_{c2} from above. This shows that the unpaired electrons sense the proximity of the field-tuned quantum critical point of CeCoIn_{5} at H^{⋆}=H_{c2} even from inside the superconducting state. The fact that the quantum critical scattering of the unpaired electrons is much weaker than the average scattering of all electrons in the normal state reveals a k-space correlation between the strength of pairing and the strength of scattering, pointing to a common mechanism, presumably antiferromagnetic fluctuations.
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Affiliation(s)
- Johnpierre Paglione
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
| | - M A Tanatar
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
- Ames Laboratory USDOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - J-Ph Reid
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
| | - H Shakeripour
- Department of Physics, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - C Petrovic
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Louis Taillefer
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
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32
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Evolution of electronic states in n-type copper oxide superconductor via electric double layer gating. Sci Rep 2016; 6:26642. [PMID: 27221198 PMCID: PMC4879525 DOI: 10.1038/srep26642] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/06/2016] [Indexed: 11/12/2022] Open
Abstract
The occurrence of electrons and holes in n-type copper oxides has been achieved by chemical doping, pressure, and/or deoxygenation. However, the observed electronic properties are blurred by the concomitant effects such as change of lattice structure, disorder, etc. Here, we report on successful tuning the electronic band structure of n-type Pr2−xCexCuO4 (x = 0.15) ultrathin films, via the electric double layer transistor technique. Abnormal transport properties, such as multiple sign reversals of Hall resistivity in normal and mixed states, have been revealed within an electrostatic field in range of −2 V to + 2 V, as well as varying the temperature and magnetic field. In the mixed state, the intrinsic anomalous Hall conductivity invokes the contribution of both electron and hole-bands as well as the energy dependent density of states near the Fermi level. The two-band model can also describe the normal state transport properties well, whereas the carrier concentrations of electrons and holes are always enhanced or depressed simultaneously in electric fields. This is in contrast to the scenario of Fermi surface reconstruction by antiferromagnetism, where an anti-correlation is commonly expected.
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Mikheev E, Hauser AJ, Himmetoglu B, Moreno NE, Janotti A, Van de Walle CG, Stemmer S. Tuning bad metal and non-Fermi liquid behavior in a Mott material: Rare-earth nickelate thin films. SCIENCE ADVANCES 2015; 1:e1500797. [PMID: 26601140 PMCID: PMC4640588 DOI: 10.1126/sciadv.1500797] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/28/2015] [Indexed: 05/05/2023]
Abstract
Resistances that exceed the Mott-Ioffe-Regel limit (known as bad metal behavior) and non-Fermi liquid behavior are ubiquitous features of the normal state of many strongly correlated materials. We establish the conditions that lead to bad metal and non-Fermi liquid phases in NdNiO3, which exhibits a prototype bandwidth-controlled metal-insulator transition. We show that resistance saturation is determined by the magnitude of Ni eg orbital splitting, which can be tuned by strain in epitaxial films, causing the appearance of bad metal behavior under certain conditions. The results shed light on the nature of a crossover to a non-Fermi liquid metal phase and provide a predictive criterion for Anderson localization. They elucidate a seemingly complex phase behavior as a function of film strain and confinement and provide guidelines for orbital engineering and novel devices.
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High performance of Mn-Co-Ni-O spinel nanofilms sputtered from acetate precursors. Sci Rep 2015; 5:10899. [PMID: 26051504 PMCID: PMC4458888 DOI: 10.1038/srep10899] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/06/2015] [Indexed: 11/17/2022] Open
Abstract
Mn-Co-Ni-O (MCN) spinel oxide material, a very important transition metal oxide (TMO) with the best application prospects in information and energy fields, was discovered over five decades ago, but its applications have been impeded by the quality of its films due to the magnitude of deposition challenge. Here we report that high quality of MCN nanofilms can be achieved by sputtering deposition via acetate precursors whose decomposition temperatures are matched to the initial synthesis temperature of the MCN thin films. Excellent performance of MCN nanofilms is demonstrated, combining for the first time preferred orientation, high temperature coefficient of resistance, and moderate resistivity. The film devices show an intrinsic recombination with a much faster rate of the order of a microsecond for the laser-pumped carriers, which is ~3 orders of magnitude larger compared with that of the ceramic material. The electronic structure of the thin films confirms that it is indeed of n-type nature, exhibiting appropriate electronic states consistent with the levels of metal electrodes and semiconductors. The results offer a vital avenue for depositing high performance TMO thin films for advanced oxide devices, and will have great significance for exploiting new applications in modern oxide electronics and optoelectronics.
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35
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Anomalous magnetoresistance in the spinel superconductor LiTi2O4. Nat Commun 2015; 6:7183. [DOI: 10.1038/ncomms8183] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 04/10/2015] [Indexed: 11/09/2022] Open
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36
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Saadaoui H, Salman Z, Luetkens H, Prokscha T, Suter A, MacFarlane WA, Jiang Y, Jin K, Greene RL, Morenzoni E, Kiefl RF. The phase diagram of electron-doped La(2-x)Ce(x)CuO(4-δ). Nat Commun 2015; 6:6041. [PMID: 25608106 DOI: 10.1038/ncomms7041] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/05/2014] [Indexed: 11/09/2022] Open
Abstract
Superconductivity is a striking example of a quantum phenomenon in which electrons move coherently over macroscopic distances without scattering. The high-temperature superconducting oxides (cuprates) are the most studied class of superconductors, composed of two-dimensional CuO2 planes separated by other layers that control the electron concentration in the planes. A key unresolved issue in cuprates is the relationship between superconductivity and magnetism. Here we report a sharp phase boundary of static three-dimensional magnetic order in the electron-doped superconductor La(2-x)Ce(x)CuO(4-δ), where small changes in doping or depth from the surface switch the material from superconducting to magnetic. Using low-energy spin-polarized muons, we find that static magnetism disappears close to where superconductivity begins and well below the doping level at which dramatic changes in the transport properties are reported. These results indicate a higher degree of symmetry between the electron and hole-doped cuprates than previously thought.
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Affiliation(s)
- H Saadaoui
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Z Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - H Luetkens
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - T Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - A Suter
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - W A MacFarlane
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Y Jiang
- Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - K Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - R L Greene
- Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - E Morenzoni
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - R F Kiefl
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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Gu D, Dai X, Le C, Sun L, Wu Q, Saparov B, Guo J, Gao P, Zhang S, Zhou Y, Zhang C, Jin S, Xiong L, Li R, Li Y, Li X, Liu J, Sefat AS, Hu J, Zhao Z. Robust antiferromagnetism preventing superconductivity in pressurized (Ba 0.61 K 0.39)Mn2Bi2. Sci Rep 2014; 4:7342. [PMID: 25475224 PMCID: PMC4256658 DOI: 10.1038/srep07342] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 11/17/2014] [Indexed: 11/09/2022] Open
Abstract
BaMn2Bi2 possesses an iso-structure of iron pnictide superconductors and similar antiferromagnetic (AFM) ground state to that of cuprates, therefore, it receives much more attention on its properties and is expected to be the parent compound of a new family of superconductors. When doped with potassium (K), BaMn2Bi2 undergoes a transition from an AFM insulator to an AFM metal. Consequently, it is of great interest to suppress the AFM order in the K-doped BaMn2Bi2 with the aim of exploring the potential superconductivity. Here, we report that external pressure up to 35.6 GPa cannot suppress the AFM order in the K-doped BaMn2Bi2 to develop superconductivity in the temperature range of 300 K-1.5 K, but induces a tetragonal (T) to an orthorhombic (OR) phase transition at ~20 GPa. Theoretical calculations for the T and OR phases, on basis of our high-pressure XRD data, indicate that the AFM order is robust in the pressurized Ba0.61K0.39Mn2Bi2. Both of our experimental and theoretical results suggest that the robust AFM order essentially prevents the emergence of superconductivity.
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Affiliation(s)
- Dachun Gu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xia Dai
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Congcong Le
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Liling Sun
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing. 100190, China
| | - Qi Wu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Bayrammurad Saparov
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 73831-6056, USA
| | - Jing Guo
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Peiwen Gao
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shan Zhang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yazhou Zhou
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Zhang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shifeng Jin
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Lun Xiong
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Li
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Yanchun Li
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaodong Li
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Liu
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Athena S. Sefat
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 73831-6056, USA
| | - Jiangping Hu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing. 100190, China
| | - Zhongxian Zhao
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing. 100190, China
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38
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Superconductivity in the vicinity of antiferromagnetic order in CrAs. Nat Commun 2014; 5:5508. [DOI: 10.1038/ncomms6508] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/08/2014] [Indexed: 11/08/2022] Open
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Candidate quantum spin liquid due to dimensional reduction of a two-dimensional honeycomb lattice. Sci Rep 2014; 4:6451. [PMID: 25245216 PMCID: PMC5377320 DOI: 10.1038/srep06451] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 09/02/2014] [Indexed: 11/11/2022] Open
Abstract
As with quantum spin liquids based on two-dimensional triangular and kagome lattices, the two-dimensional honeycomb lattice with either a strong spin-orbital coupling or a frustrating second-nearest-neighbor coupling is expected to be a source of candidate quantum spin liquids. An ammonium salt [(C3H7)3NH]2[Cu2(C2O4)3](H2O)2.2 containing hexagonal layers of Cu2+ was obtained from solution. No structural transition or long-range magnetic ordering was observed from 290 K to 2 K from single crystal X-ray diffraction, specific heat and susceptibility measurements. The anionic layers are separated by sheets of ammonium and H2O with distance of 3.5 Å and no significant interaction between anionic layers. The two-dimensional honeycomb lattice is constructed from Jahn-Teller distorted Cu2+ and oxalate anions, showing a strong antiferromagnetic interaction between S = 1/2 metal atoms with θ = −120 (1) K. Orbital analysis of the Cu2+ interactions through the oxalate-bridges suggests a stripe mode pattern of coupling with weak ferromagnetic interaction along the b axis, and strong antiferromagnetic interaction along the a axis. Analysis of the magnetic susceptibility shows that it is dominated by a quasi-one-dimensional contribution with spin chains that are at least as well isolated as those of well-known quasi-one-dimensional spin liquids.
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40
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Anisotropic breakdown of Fermi liquid quasiparticle excitations in overdoped La₂-xSrxCuO₄. Nat Commun 2014; 4:2559. [PMID: 24096628 DOI: 10.1038/ncomms3559] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/04/2013] [Indexed: 11/09/2022] Open
Abstract
High-temperature superconductivity emerges from an un-conventional metallic state. This has stimulated strong efforts to understand exactly how Fermi liquids breakdown and evolve into an un-conventional metal. A fundamental question is how Fermi liquid quasiparticle excitations break down in momentum space. Here we show, using angle-resolved photoemission spectroscopy, that the Fermi liquid quasiparticle excitations of the overdoped superconducting cuprate La1.77Sr0.23CuO4 is highly anisotropic in momentum space. The quasiparticle scattering and residue behave differently along the Fermi surface and hence the Kadowaki-Wood's relation is not obeyed. This kind of Fermi liquid breakdown may apply to a wide range of strongly correlated metal systems where spin fluctuations are present.
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41
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Gao P, Sun L, Ni N, Guo J, Wu Q, Zhang C, Gu D, Yang K, Li A, Jiang S, Cava RJ, Zhao Z. Pressure-induced superconductivity and its scaling with doping-induced superconductivity in the iron pnictide with skutterudite intermediary layers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2346-2351. [PMID: 24469882 DOI: 10.1002/adma.201305154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/20/2013] [Indexed: 06/03/2023]
Abstract
Pressure-induced superconductivity is oberserved in Ca10 (Pt3 As8 )(Fe2 As2 )5 by in situ high-pressure resistance and magnetic susceptibility measurements. Scaling of the pressure-induced and doping-induced superconductivity shows that the electronic phase diagrams of the pressurized and chemically doped 10-3-8 compound are similar in the moderate pressure and doping range but are disparate at higher pressure and heavy doping.
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Affiliation(s)
- Peiwen Gao
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, China
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42
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Emerging superconductivity hidden beneath charge-transfer insulators. Sci Rep 2014; 3:2235. [PMID: 23887134 PMCID: PMC3724181 DOI: 10.1038/srep02235] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 07/01/2013] [Indexed: 11/23/2022] Open
Abstract
In many of today's most interesting materials, strong interactions prevail upon the magnetic moments, the electrons, and the crystal lattice, forming strong links between these different aspects of the system. Particularly, in two-dimensional cuprates, where copper is either five- or six-fold coordinated, superconductivity is commonly induced by chemical doping which is deemed to be mandatory by destruction of long-range antiferromagnetic order of 3d9 Cu2+ moments. Here we show that superconductivity can be induced in Pr2CuO4, where copper is four-fold coordinated. We induced this novel quantum state of Pr2CuO4 by realizing pristine square-planar coordinated copper in the copper-oxygen planes, thus, resulting in critical superconducting temperatures even higher than by chemical doping. Our results demonstrate new degrees of freedom, i.e., coordination of copper, for the manipulation of magnetic and superconducting order parameters in quantum materials.
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43
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Wang LM, Wang CY, Sou UC, Yang HC, Chang LJ, Redding C, Song Y, Dai P, Zhang C. Longitudinal and transverse Hall resistivities in NaFe₁-xCoxAs single crystals with x = 0.022 and 0.0205: weak pinning and anomalous electrical transport properties. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:395702. [PMID: 24002242 DOI: 10.1088/0953-8984/25/39/395702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The in-plane longitudinal and Hall resistivities, ρxx and ρxy, of superconducting NaFe1-xCoxAs (NFCA) single crystals with x = 0.022 and 0.0205 in the mixed state and the normal state were measured to study the electrical transport properties in nearly optimum-doping iron-based superconductors. The resistivities under magnetic fields show thermally activated behavior and a power law magnetic field dependence of activation energy has been obtained. Due to the weak flux pinning, there is no sign reversal of Hall resistivities observed for NFCA with either x = 0.022 or 0.0205. The correlation between longitudinal and Hall resistivities shows that the scaling behavior of |ρxy| ∝ (ρxx)(β) with the exponent β ≈ 2.0 is in agreement with theoretical predictions for weak-pinning superconductors. Anisotropic upper critical fields and coherence lengths with an anisotropy ratio of γ ≈ 1.63 have been deduced. Furthermore, the normal-state transport properties show that the anomalies of the linear-T resistivity, the T(2)-dependent cotangent of the Hall angle, the linear-T-like Hall number, and the magnetoresistance, which can be scaled by the modified Kohler rule, are analogous to those observed on optimally doped high-Tc superconducting cuprates and other pnictides. The longitudinal resistivity can be understood within a widely accepted scenario of the spin density-wave quantum critical point, while the transverse resistivity requires some further explanation. It is suggested that all the transport anomalies should be simultaneously taken into account when developing theory.
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Affiliation(s)
- L M Wang
- Graduate Institute of Applied Physics/Department of Physics, National Taiwan University, Taipei 106, Taiwan
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44
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Dai YM, Xu B, Shen B, Xiao H, Wen HH, Qiu XG, Homes CC, Lobo RPSM. Hidden T-linear scattering rate in Ba0.6K0.4Fe2As2 revealed by optical spectroscopy. PHYSICAL REVIEW LETTERS 2013; 111:117001. [PMID: 24074114 DOI: 10.1103/physrevlett.111.117001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Indexed: 06/02/2023]
Abstract
The optical properties of Ba0.6K0.4Fe2As2 have been determined in the normal state for a number of temperatures over a wide frequency range. Two Drude terms, representing two groups of carriers with different scattering rates (1/τ), well describe the real part of the optical conductivity σ1(ω). A "broad" Drude component results in an incoherent background with a T-independent 1/τb, while a "narrow" Drude component reveals a T-linear 1/τn resulting in a resistivity ρn≡1/σ1n(ω→0) also linear in temperature. An arctan(T) low-frequency spectral weight is also strong evidence for a T-linear 1/τ. A comparison to other materials with similar behavior suggests that the T-linear 1/τn and ρn in Ba0.6K0.4Fe2As2 originate from scattering from spin fluctuations and hence that an antiferromagnetic quantum critical point is likely to exist in the superconducting dome.
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Affiliation(s)
- Y M Dai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China and LPEM, ESPCI-ParisTech, CNRS, UPMC, 10 rue Vauquelin, F-75231 Paris Cedex 5, France and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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Hussey NE, Gordon-Moys H, Kokalj J, McKenzie RH. Generic strange-metal behaviour of overdoped cuprates. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/449/1/012004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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46
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Guo J, Qi Y, Matsuishi S, Hosono H. T(c) maximum in solid solution of pyrite IrSe2-RhSe2 induced by destabilization of anion dimers. J Am Chem Soc 2012. [PMID: 23186075 DOI: 10.1021/ja309724w] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have established a well-defined dome-shaped T(c) curve in Ir(0.94-x)Rh(x)Se(2) superconductors. The maximum T(c)(onset) of 9.6 K was obtained at x = 0.36, at which the Se-Se separation in the dimer anion is the longest. Simultaneously, the destabilization of Se-Se dimers accompanied by partial electron transfer from the Ir/Rh to the chalcogenide ions resulted in the emergence of optimal T(c).
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Affiliation(s)
- Jiangang Guo
- Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8503, Japan
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47
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Sachdev S, Metlitski MA, Punk M. Antiferromagnetism in metals: from the cuprate superconductors to the heavy fermion materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:294205. [PMID: 22773369 DOI: 10.1088/0953-8984/24/29/294205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The critical theory of the onset of antiferromagnetism in metals, with concomitant Fermi surface reconstruction, has recently been shown to be strongly coupled in two spatial dimensions. The onset of unconventional superconductivity near this critical point is reviewed: it involves a subtle interplay between the breakdown of fermionic quasiparticle excitations on the Fermi surface and the strong pairing glue provided by the antiferromagnetic fluctuations. The net result is a logarithm-squared enhancement of the pairing vertex for generic Fermi surfaces, with a universal dimensionless coefficient independent of the strength of interactions, which is expected to lead to superconductivity at the scale of the Fermi energy. We also discuss the possibility that the antiferromagnetic critical point can be replaced by an intermediate 'fractionalized Fermi liquid' phase, in which there is Fermi surface reconstruction but no long-range antiferromagnetic order. We discuss the relevance of this phase to the underdoped cuprates and the heavy fermion materials.
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Affiliation(s)
- Subir Sachdev
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.
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Shan L, Gong J, Wang YL, Shen B, Hou X, Ren C, Li C, Yang H, Wen HH, Li S, Dai P. Evidence of a spin resonance mode in the iron-based superconductor Ba(0.6)K(0.4)Fe2As2 from scanning tunneling spectroscopy. PHYSICAL REVIEW LETTERS 2012; 108:227002. [PMID: 23003642 DOI: 10.1103/physrevlett.108.227002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Indexed: 06/01/2023]
Abstract
We used high-resolution scanning tunneling spectroscopy to study the hole-doped iron pnictide superconductor Ba(0.6)K(0.4)Fe(2)As(2) (T(c)=38 K). Features of a bosonic excitation (mode) are observed in the measured quasiparticle density of states. The bosonic features are intimately associated with the superconducting order parameter and have a mode energy of ~14 meV, similar to the spin resonance measured by inelastic neutron scattering. These results indicate a strong electron-spin excitation coupling in iron pnictide superconductors, similar to that in high-T(c) copper oxide superconductors.
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Affiliation(s)
- Lei Shan
- National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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Guo J, Chen XJ, Dai J, Zhang C, Guo J, Chen X, Wu Q, Gu D, Gao P, Yang L, Yang K, Dai X, Mao HK, Sun L, Zhao Z. Pressure-driven quantum criticality in iron-selenide superconductors. PHYSICAL REVIEW LETTERS 2012; 108:197001. [PMID: 23003077 DOI: 10.1103/physrevlett.108.197001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 02/16/2012] [Indexed: 06/01/2023]
Abstract
We report a finding of a pressure-induced quantum critical transition in K0.8Fe(x)Se2 (x = 1.7 and 1.78) superconductors through in situ high-pressure electrical transport and x-ray diffraction measurements in diamond anvil cells. Transitions from metallic Fermi liquid behavior to non-Fermi liquid behavior and from antiferromagnetism to paramagnetism are found in the pressure range of 9.2-10.3 GPa, in which superconductivity tends to disappear. The change around the quantum critical point from the coexisting antiferromagnetism state and the Fermi liquid behavior to the paramagnetism state and the non-Fermi liquid behavior in the iron-selenide superconductors demonstrates a unique mechanism for their quantum critical transition.
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Affiliation(s)
- Jing Guo
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
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Quantum critical scaling at the edge of Fermi liquid stability in a cuprate superconductor. Proc Natl Acad Sci U S A 2012; 109:8440-4. [PMID: 22573818 DOI: 10.1073/pnas.1120273109] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the high-temperature cuprate superconductors, the pervasiveness of anomalous electronic transport properties suggests that violation of conventional Fermi liquid behavior is closely tied to superconductivity. In other classes of unconventional superconductors, atypical transport is well correlated with proximity to a quantum critical point, but the relative importance of quantum criticality in the cuprates remains uncertain. Here, we identify quantum critical scaling in the electron-doped cuprate material La(2-x)Ce(x)CuO(4) with a line of quantum critical points that surrounds the superconducting phase as a function of magnetic field and charge doping. This zero-temperature phase boundary, which delineates a metallic Fermi liquid regime from an extended non-Fermi liquid ground state, closely follows the upper critical field of the overdoped superconducting phase and gives rise to an expanse of distinct non-Fermi liquid behavior at finite temperatures. Together with signatures of two distinct flavors of quantum fluctuations, these facts suggest that quantum criticality plays a significant role in shaping the anomalous properties of the cuprate phase diagram.
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