1
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Li XT, Tu SJ, Chaix L, Fawaz C, d'Astuto M, Li X, Yakhou-Harris F, Kummer K, Brookes NB, Garcia-Fernandez M, Zhou KJ, Lin ZF, Yuan J, Jin K, Dean MPM, Liu X. Evolution of the Magnetic Excitations in Electron-Doped La_{2-x}Ce_{x}CuO_{4}. PHYSICAL REVIEW LETTERS 2024; 132:056002. [PMID: 38364146 DOI: 10.1103/physrevlett.132.056002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/12/2023] [Indexed: 02/18/2024]
Abstract
We investigated the high energy spin excitations in electron-doped La_{2-x}Ce_{x}CuO_{4}, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip spectral weight mixing in the RIXS spectrum at Q_{∥}=(0.6π,0) and (0.9π,0) along the (1 0) direction. Our results show that, for doping level x from 0.07 to 0.185, the variation of the paramagnon excitation energy is marginal. We discuss the implication of our results in connection with the evolution of the electron correlation strength in this system.
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Affiliation(s)
- X T Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - S J Tu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - L Chaix
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - C Fawaz
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - M d'Astuto
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - X Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - F Yakhou-Harris
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | - N B Brookes
- European Synchrotron Radiation Facility (ESRF), B.P. 220, F-38043 Grenoble Cedex, France
| | | | - Ke-Jin Zhou
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - Z F Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J Yuan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - K Jin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - M P M Dean
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - X Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Center for Transformative Science, ShanghaiTech University, Shanghai 201210, China
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2
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Yan H, Bok JM, He J, Zhang W, Gao Q, Luo X, Cai Y, Peng Y, Meng J, Li C, Chen H, Song C, Yin C, Miao T, Chen Y, Gu G, Lin C, Zhang F, Yang F, Zhang S, Peng Q, Liu G, Zhao L, Choi HY, Xu Z, Zhou XJ. Ubiquitous coexisting electron-mode couplings in high-temperature cuprate superconductors. Proc Natl Acad Sci U S A 2023; 120:e2219491120. [PMID: 37851678 PMCID: PMC10614907 DOI: 10.1073/pnas.2219491120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 09/12/2023] [Indexed: 10/20/2023] Open
Abstract
In conventional superconductors, electron-phonon coupling plays a dominant role in generating superconductivity. In high-temperature cuprate superconductors, the existence of electron coupling with phonons and other boson modes and its role in producing high-temperature superconductivity remain unclear. The evidence of electron-boson coupling mainly comes from angle-resolved photoemission (ARPES) observations of [Formula: see text]70-meV nodal dispersion kink and [Formula: see text]40-meV antinodal kink. However, the reported results are sporadic and the nature of the involved bosons is still under debate. Here we report findings of ubiquitous two coexisting electron-mode couplings in cuprate superconductors. By taking ultrahigh-resolution laser-based ARPES measurements, we found that the electrons are coupled simultaneously with two sharp modes at [Formula: see text]70meV and [Formula: see text]40meV in different superconductors with different dopings, over the entire momentum space and at different temperatures above and below the superconducting transition temperature. These observations favor phonons as the origin of the modes coupled with electrons and the observed electron-mode couplings are unusual because the associated energy scales do not exhibit an obvious energy shift across the superconducting transition. We further find that the well-known "peak-dip-hump" structure, which has long been considered a hallmark of superconductivity, is also omnipresent and consists of "peak-double dip-double hump" finer structures that originate from electron coupling with two sharp modes. These results provide a unified picture for the [Formula: see text]70-meV and [Formula: see text]40-meV energy scales and their evolutions with momentum, doping and temperature. They provide key information to understand the origin of these energy scales and their role in generating anomalous normal state and high-temperature superconductivity.
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Affiliation(s)
- Hongtao Yan
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Jin Mo Bok
- Department of Physics, Pohang University of Science and Technology, Pohang37673, Korea
| | - Junfeng He
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Wentao Zhang
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Qiang Gao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Xiangyu Luo
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yongqing Cai
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Yingying Peng
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Jianqiao Meng
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Cong Li
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Hao Chen
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Chunyao Song
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Chaohui Yin
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Taimin Miao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yiwen Chen
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Genda Gu
- Condensed Matter Physics, Materials Science Division of Brookhaven National Laboratory, Upton, NY11973-5000
| | - Chengtian Lin
- Max Planck Institute for Solid State Research, D-70569Stuttgart, Germany
| | - Fengfeng Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - Guodong Liu
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
| | - Lin Zhao
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
| | - Han-Yong Choi
- Department of Physics, Sungkyunkwan University, Suwon16419, Korea
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100190, China
| | - X. J. Zhou
- National Lab for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Songshan Lake Materials Laboratory, Dongguan523808, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
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3
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Ong BL, Jayaraman K, Diao C, Whitcher TJ, Jain A, Hung H, Breese MBH, Tok ES, Rusydi A. Anomalous Ferromagnetism of quasiparticle doped holes in cuprate heterostructures revealed using resonant soft X-ray magnetic scattering. Nat Commun 2022; 13:4639. [PMID: 35941141 PMCID: PMC9360448 DOI: 10.1038/s41467-022-31885-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 07/04/2022] [Indexed: 11/09/2022] Open
Abstract
We report strong ferromagnetism of quasiparticle doped holes both within the ab-plane and along the c-axis of Cu-O planes in low-dimensional Au/d-La1.8Ba0.2CuO4/LaAlO3(001) heterostructures (d = 4, 8 and 12 unit-cells) using resonant soft X-ray and magnetic scattering together with X-ray magnetic circular dichroism. Interestingly, ferromagnetism is stronger at a hole doped peak and at an upper Hubbard band of O with spin-polarization degree as high as 40%, revealing strong ferromagnetism of Mottness. For in-ab-plane spin-polarizations, the spin of doped holes in O2p-Cu3d-O2p is a triplet state yielding strong ferromagnetism. For out-of-ab-plane spin-polarization, while the spins of doped holes in both O2p-O2p and Cu3d-Cu3d are triplet states, the spin of doped holes in Cu3d-O2p is a singlet state yielding ferrimagnetism. A ferromagnetic-(002) Bragg-peak of the doped holes is observed and enhanced as a function of d revealing strong ferromagnetism coupling between Cu-O layers along the c-axis.
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Affiliation(s)
- B L Ong
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - K Jayaraman
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - C Diao
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - T J Whitcher
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - A Jain
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - H Hung
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - M B H Breese
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - E S Tok
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - A Rusydi
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore. .,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore. .,Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore.
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4
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Barišić N, Sunko DK. High-T c Cuprates: a Story of Two Electronic Subsystems. JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM 2022; 35:1781-1799. [PMID: 35756097 PMCID: PMC9217785 DOI: 10.1007/s10948-022-06183-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/12/2022] [Indexed: 06/15/2023]
Abstract
A review of the phenomenology and microscopy of cuprate superconductors is presented, with particular attention to universal conductance features, which reveal the existence of two electronic subsystems. The overall electronic system consists of 1 + p charges, where p is the doping. At low dopings, exactly one hole is localized per planar copper-oxygen unit, while upon increasing doping and temperature, the hole is gradually delocalized and becomes itinerant. Remarkably, the itinerant holes exhibit identical Fermi liquid character across the cuprate phase diagram. This universality enables a simple count of carrier density and yields comprehensive understanding of the key features in the normal and superconducting state. A possible superconducting mechanism is presented, compatible with the key experimental facts. The base of this mechanism is the interaction of fast Fermi liquid carriers with localized holes. A change in the microscopic nature of chemical bonding in the copper oxide planes, from ionic to covalent, is invoked to explain the phase diagram of these fascinating compounds.
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Affiliation(s)
- N. Barišić
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb, 10000 Croatia
- Institute of Solid State Physics, TU Wien, Vienna, 1040 Austria
| | - D. K. Sunko
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb, 10000 Croatia
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5
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Mishchenko AS, Tupitsyn IS, Nagaosa N, Prokof'ev N. Fermi blockade of the strong electron-phonon interaction in modelled optimally doped high temperature superconductors. Sci Rep 2021; 11:9699. [PMID: 33958643 PMCID: PMC8102534 DOI: 10.1038/s41598-021-89059-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/16/2021] [Indexed: 11/09/2022] Open
Abstract
We study how manifestations of strong electron-phonon interaction depend on the carrier concentration by solving the two-dimensional Holstein model for the spin-polarized fermions using an approximation free bold-line diagrammatic Monte Carlo method. We show that the strong electron-phonon interaction, obviously present at very small Fermion concentration, is masked by the Fermi blockade effects and Migdal's theorem to the extent that it manifests itself as moderate one at large carriers densities. Suppression of strong electron-phonon interaction fingerprints is in agreement with experimental observations in doped high temperature superconductors.
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Affiliation(s)
- Andrey S Mishchenko
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan.
| | - Igor S Tupitsyn
- Department of Physics, University of Massachusetts, Amherst, MA, 01003, USA
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan.,Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Nikolay Prokof'ev
- Department of Physics, University of Massachusetts, Amherst, MA, 01003, USA
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6
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Jiang M, Berciu M, Sawatzky GA. Critical Nature of the Ni Spin State in Doped NdNiO_{2}. PHYSICAL REVIEW LETTERS 2020; 124:207004. [PMID: 32501091 DOI: 10.1103/physrevlett.124.207004] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/20/2019] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Superconductivity with T_{c}≈15 K was recently found in doped NdNiO_{2}. The Ni^{1+}O_{2} layers are expected to be Mott insulators, so hole doping should produce Ni^{2+} with S=1, incompatible with robust superconductivity. We show that the NiO_{2} layers fall inside a critical region where the large pd hybridization favors a singlet ^{1}A_{1} hole-doped state like in CuO_{2}. However, we find that the superexchange is about one order smaller than in cuprates, thus a magnon "glue" is very unlikely and another mechanism needs to be found.
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Affiliation(s)
- Mi Jiang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Mona Berciu
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - George A Sawatzky
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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7
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Rossi M, Arpaia R, Fumagalli R, Moretti Sala M, Betto D, Kummer K, De Luca GM, van den Brink J, Salluzzo M, Brookes NB, Braicovich L, Ghiringhelli G. Experimental Determination of Momentum-Resolved Electron-Phonon Coupling. PHYSICAL REVIEW LETTERS 2019; 123:027001. [PMID: 31386544 DOI: 10.1103/physrevlett.123.027001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 06/10/2023]
Abstract
We provide a novel experimental method to quantitatively estimate the electron-phonon coupling and its momentum dependence from resonant inelastic x-ray scattering (RIXS) spectra based on the detuning of the incident photon energy away from an absorption resonance. We apply it to the cuprate parent compound NdBa_{2}Cu_{3}O_{6} and find that the electronic coupling to the oxygen half-breathing phonon branch is strongest at the Brillouin zone boundary, where it amounts to ∼0.17 eV, in agreement with previous studies. In principle, this method is applicable to any absorption resonance suitable for RIXS measurements and will help to define the contribution of lattice vibrations to the peculiar properties of quantum materials.
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Affiliation(s)
- Matteo Rossi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Riccardo Arpaia
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Roberto Fumagalli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Marco Moretti Sala
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Davide Betto
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Kurt Kummer
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Gabriella M De Luca
- Dipartimento di Fisica "E. Pancini," Università degli Studi di Napoli "Federico II," Complesso Monte Sant'Angelo-Via Cinthia, I-80126 Napoli, Italy
- CNR-SPIN, Complesso Monte Sant'Angelo-Via Cinthia, I-80126 Napoli, Italy
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany
- Department of Physics, Technical University Dresden, D-01062 Dresden, Germany
| | - Marco Salluzzo
- CNR-SPIN, Complesso Monte Sant'Angelo-Via Cinthia, I-80126 Napoli, Italy
| | - Nicholas B Brookes
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Lucio Braicovich
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Giacomo Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
- CNR-SPIN, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
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8
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Huang J, Zhao L, Li C, Gao Q, Liu J, Hu Y, Xu Y, Cai Y, Wu D, Ding Y, Hu C, Zhou H, Dong X, Liu G, Wang Q, Zhang S, Wang Z, Zhang F, Yang F, Peng Q, Xu Z, Chen C, Zhou X. Emergence of superconductivity from fully incoherent normal state in an iron-based superconductor (Ba 0.6K 0.4)Fe 2As 2. Sci Bull (Beijing) 2019; 64:11-19. [PMID: 36659518 DOI: 10.1016/j.scib.2018.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/24/2018] [Accepted: 11/26/2018] [Indexed: 01/21/2023]
Abstract
In unconventional superconductors, it is generally believed that understanding the physical properties of the normal state is a pre-requisite for understanding the superconductivity mechanism. In conventional superconductors like niobium or lead, the normal state is a Fermi liquid with a well-defined Fermi surface and well-defined quasipartcles along the Fermi surface. Superconductivity is realized in this case by the Fermi surface instability in the superconducting state and the formation and condensation of the electron pairs (Cooper pairing). The high temperature cuprate superconductors, on the other hand, represent another extreme case that superconductivity can be realized in the underdoped region where there is neither well-defined Fermi surface due to the pseudogap formation nor quasiparticles near the antinodal regions in the normal state. Here we report a novel scenario that superconductivity is realized in a system with well-defined Fermi surface but without quasiparticles along the Fermi surface in the normal state. High resolution laser-based angle-resolved photoemission measurements have been performed on an optimally-doped iron-based superconductor (Ba0.6K0.4)Fe2As2. We find that, while sharp superconducting coherence peaks emerge in the superconducting state on the hole-like Fermi surface sheets, no quasiparticle peak is present in the normal state. Its electronic behaviours deviate strongly from a Fermi liquid system. The superconducting gap of such a system exhibits an unusual temperature dependence that it is nearly a constant in the superconducting state and abruptly closes at Tc. These observations have provided a new platform to study unconventional superconductivity in a non-Fermi liquid system.
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Affiliation(s)
- Jianwei Huang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Cong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiang Gao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongqing Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dingsong Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Ding
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cheng Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huaxue Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoli Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guodong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qingyan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhimin Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Fengfeng Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chuangtian Chen
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
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9
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Abstract
Identifying the gap structure of superconductors is vital for understanding the underlying pairing mechanism of the Cooper pairs. The first heavy fermion superconductor to be discovered, CeCu2Si2, was thought to be a d-wave superconductor with gap nodes, until recent specific heat measurements provided evidence that the gap is fully open across the Fermi surface. We propose a resolution to this puzzle from measurements of the London penetration depth, which give further evidence for fully gapped superconductivity. We analyze the data using a d-wave band-mixing pairing model, which leads to a fully open superconducting gap. Our model accounts well for the penetration depth and specific heat data, while reconciling the nodeless and sign-changing nature of the gap function. The nature of the pairing symmetry of the first heavy fermion superconductor CeCu2Si2 has recently become the subject of controversy. While CeCu2Si2 was generally believed to be a d-wave superconductor, recent low-temperature specific heat measurements showed evidence for fully gapped superconductivity, contrary to the nodal behavior inferred from earlier results. Here, we report London penetration depth measurements, which also reveal fully gapped behavior at very low temperatures. To explain these seemingly conflicting results, we propose a fully gapped d+d band-mixing pairing state for CeCu2Si2, which yields very good fits to both the superfluid density and specific heat, as well as accounting for a sign change of the superconducting order parameter, as previously concluded from inelastic neutron scattering results.
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10
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Entropic Origin of Pseudogap Physics and a Mott-Slater Transition in Cuprates. Sci Rep 2017; 7:44008. [PMID: 28327627 PMCID: PMC5361159 DOI: 10.1038/srep44008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/02/2017] [Indexed: 11/30/2022] Open
Abstract
We propose a new approach to understand the origin of the pseudogap in the cuprates, in terms of bosonic entropy. The near-simultaneous softening of a large number of different q-bosons yields an extended range of short-range order, wherein the growth of magnetic correlations with decreasing temperature T is anomalously slow. These entropic effects cause the spectral weight associated with the Van Hove singularity (VHS) to shift rapidly and nearly linearly toward half filling at higher T, consistent with a picture of the VHS driving the pseudogap transition at a temperature ~T*. As a byproduct, we develop an order-parameter classification scheme that predicts supertransitions between families of order parameters. As one example, we find that by tuning the hopping parameters, it is possible to drive the cuprates across a transition between Mott and Slater physics, where a spin-frustrated state emerges at the crossover.
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11
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Fanfarillo L, Mori M, Campetella M, Grilli M, Caprara S. Glue function of optimally and overdoped cuprates from inversion of the Raman spectra. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:065701. [PMID: 26790363 DOI: 10.1088/0953-8984/28/6/065701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We address the issue of identifying the mediators of effective interactions in cuprates superconductors. Specifically, we use inversion theory to analyze Raman spectra of optimally and over-doped La2-x Sr x CuO4 samples. This allows us to extract the so-called glue function without making any a priori assumption based on any specific model. We use instead two different techniques, namely the singular value decomposition and a multi-rectangle decomposition. With both techniques we find consistent results showing that: (i) two distinct excitations are responsible for the glue function, which have completely different doping dependence. One excitation becomes weak above optimal doping, where on the contrary the other keeps (or even slightly increases) its strength; (ii) there is a marked temperature dependence on the weight and spectral distribution of these excitations, which therefore must have a somewhat critical character. It is quite natural to identify and characterize these two distinct excitations as damped antiferromagnetic spin waves and damped charge density waves, respectively. This sets the stage for a scenario in which superconductivity is concomitant and competing with a charge ordering instability.
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Affiliation(s)
- L Fanfarillo
- Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, E-28049 Madrid, Spain
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12
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Butler MR, Movaghar B, Marks TJ, Ratner MA. Electron pairing in designer materials: a novel strategy for a negative effective Hubbard U. NANO LETTERS 2015; 15:1597-1602. [PMID: 25615444 DOI: 10.1021/nl5041176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose a set of design rules with a model Hamiltonian that allows electrons to form attracting pairs through the exploitation of a new combination of resonant band alignment and Coulombic repulsion. The pair bands and single particle bands in various lattices are calculated and compared in energy, and regions of net attraction are identified. This work provides guidelines for the construction of molecular systems, nanocrystals, and nanoparticle arrays with the potential for superconductivity.
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Affiliation(s)
- Melanie R Butler
- Department of Chemistry and the Materials Research Center, Northwestern University , Evanston, Illinois 60208, United States
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13
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From quantum matter to high-temperature superconductivity in copper oxides. Nature 2015; 518:179-86. [PMID: 25673411 DOI: 10.1038/nature14165] [Citation(s) in RCA: 468] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/22/2014] [Indexed: 11/09/2022]
Abstract
The discovery of high-temperature superconductivity in the copper oxides in 1986 triggered a huge amount of innovative scientific inquiry. In the almost three decades since, much has been learned about the novel forms of quantum matter that are exhibited in these strongly correlated electron systems. A qualitative understanding of the nature of the superconducting state itself has been achieved. However, unresolved issues include the astonishing complexity of the phase diagram, the unprecedented prominence of various forms of collective fluctuations, and the simplicity and insensitivity to material details of the 'normal' state at elevated temperatures.
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14
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Guarise M, Piazza BD, Berger H, Giannini E, Schmitt T, Rønnow HM, Sawatzky GA, van den Brink J, Altenfeld D, Eremin I, Grioni M. Anisotropic softening of magnetic excitations along the nodal direction in superconducting cuprates. Nat Commun 2014; 5:5760. [DOI: 10.1038/ncomms6760] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 11/05/2014] [Indexed: 11/09/2022] Open
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15
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Nature of strong hole pairing in doped Mott antiferromagnets. Sci Rep 2014; 4:5419. [PMID: 24957467 PMCID: PMC4067615 DOI: 10.1038/srep05419] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/03/2014] [Indexed: 11/08/2022] Open
Abstract
Cooper pairing instability in a Fermi liquid is well understood by the BCS theory, but pairing mechanism for doped Mott insulators still remains elusive. Previously it has been shown by density matrix renormalization group (DMRG) method that a single doped hole is always self-localized due to the quantum destructive interference of the phase string signs hidden in the t-J ladders. Here we report a DMRG investigation of hole binding in the same model, where a novel pairing-glue scheme beyond the BCS realm is discovered. Specifically, we show that, in addition to spin pairing due to superexchange interaction, the strong frustration of the phase string signs on the kinetic energy gets effectively removed by pairing the charges, which results in strong binding of two holes. By contrast, if the phase string signs are "switched off" artificially, the pairing strength diminishes significantly even if the superexchange coupling remains the same. In the latter, unpaired holes behave like coherent quasiparticles with pairing drastically weakened, whose sole origin may be attributed to the resonating-valence-bond (RVB) pairing of spins. Such non-BCS pairing mechanism is therefore beyond the RVB picture and may shed important light on the high-T(c) cuprate superconductors.
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16
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Yu R, Goswami P, Si Q, Nikolic P, Zhu JX. Superconductivity at the border of electron localization and itinerancy. Nat Commun 2014; 4:2783. [PMID: 24231858 DOI: 10.1038/ncomms3783] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 10/16/2013] [Indexed: 11/09/2022] Open
Abstract
The superconducting state of iron pnictides and chalcogenides exists at the border of anti-ferromagnetic order. Consequently, these materials could provide clues about the relationship between magnetism and unconventional superconductivity. One explanation, motivated by the so-called bad metal behaviour of these materials proposes that magnetism and superconductivity develop out of quasi-localized magnetic moments that are generated by strong electron-electron correlations. Another suggests that these phenomena are the result of weakly interacting electron states that lie on nested Fermi surfaces. Here we address the issue by comparing the newly discovered alkaline iron selenide superconductors, which exhibit no Fermi-surface nesting, to their iron pnictide counterparts. We show that the strong-coupling approach leads to similar pairing amplitudes in these materials, despite their different Fermi surfaces. We also find that the pairing amplitudes are largest at the boundary between electronic localization and itinerancy, suggesting that new superconductors might be found in materials with similar characteristics.
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Affiliation(s)
- Rong Yu
- 1] Department of Physics, Renmin University of China, Beijing 100872, China [2] Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA [3]
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17
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Mazzola F, Wells JW, Yakimova R, Ulstrup S, Miwa JA, Balog R, Bianchi M, Leandersson M, Adell J, Hofmann P, Balasubramanian T. Kinks in the σ band of graphene induced by electron-phonon coupling. PHYSICAL REVIEW LETTERS 2013; 111:216806. [PMID: 24313515 DOI: 10.1103/physrevlett.111.216806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Indexed: 05/09/2023]
Abstract
Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the σ band of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and the cutoff in the Fermi-Dirac distribution. They are therefore not expected for the σ band of graphene that has a binding energy of more than ≈3.5 eV. We argue that the observed kinks are indeed caused by the electron-phonon interaction, but the role of the Fermi-Dirac distribution cutoff is assumed by a cutoff in the density of σ states. The existence of the effect suggests a very weak coupling of holes in the σ band not only to the π electrons of graphene but also to the substrate electronic states. This is confirmed by the presence of such kinks for graphene on several different substrates that all show a strong coupling constant of λ≈1.
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Affiliation(s)
- Federico Mazzola
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway
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18
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Hong SH, Choi HY. Angle and frequency dependence of self-energy from spin fluctuation mediated d-wave pairing for high temperature superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:365702. [PMID: 23934792 DOI: 10.1088/0953-8984/25/36/365702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigated the characteristics of spin fluctuation mediated superconductivity employing the Eliashberg formalism. The effective interaction between electrons was modeled in terms of the spin susceptibility measured by inelastic neutron scattering experiments on single crystal La(2-x)Sr(x)CuO4 superconductors. The diagonal self-energy and off-diagonal self-energy were calculated by solving the coupled Eliashberg equation self-consistently for the chosen spin susceptibility and tight-binding dispersion of electrons. The full momentum and frequency dependence of the self-energy is presented for optimally doped, overdoped, and underdoped LSCO cuprates in a superconductive state. These results may be compared with the experimentally deduced self-energy from ARPES experiments.
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Affiliation(s)
- Seung Hwan Hong
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
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19
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He J, Zhang W, Bok JM, Mou D, Zhao L, Peng Y, He S, Liu G, Dong X, Zhang J, Wen JS, Xu ZJ, Gu GD, Wang X, Peng Q, Wang Z, Zhang S, Yang F, Chen C, Xu Z, Choi HY, Varma CM, Zhou XJ. Coexistence of two sharp-mode couplings and their unusual momentum dependence in the superconducting state of Bi2Sr2CaCu2O(8+δ) revealed by laser-based angle-resolved photoemission. PHYSICAL REVIEW LETTERS 2013; 111:107005. [PMID: 25166699 DOI: 10.1103/physrevlett.111.107005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/12/2013] [Indexed: 06/03/2023]
Abstract
High-resolution laser-based angle-resolved photoemission measurements have been carried out on Bi2Sr2CaCu2O(8+δ) (Bi2212) superconductors to investigate momentum dependence of electron coupling with collective excitations (modes). Two coexisting energy scales are clearly revealed over a large momentum space for the first time in the superconducting state of the overdoped Bi2212 superconductor. These two energy scales exhibit distinct momentum dependence: one keeps its energy near 78 meV over a large momentum space while the other changes its energy from ∼40 meV near the antinodal region to ∼70 meV near the nodal region. These observations provide a new picture on momentum evolution of electron-boson coupling in Bi2212 that electrons are coupled with two sharp modes simultaneously over a large momentum space in the superconducting states. Their unusual momentum dependence poses a challenge to our current understanding of electron-mode-coupling and its role for high-temperature superconductivity in cuprate superconductors.
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Affiliation(s)
- Junfeng He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Wentao Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Jin Mo Bok
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - Daixiang Mou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Lin Zhao
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Yingying Peng
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Shaolong He
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Guodong Liu
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Xiaoli Dong
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Jun Zhang
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - J S Wen
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Z J Xu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G D Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Xiaoyang Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Zhimin Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Chuangtian Chen
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China
| | - H-Y Choi
- Department of Physics and Institute for Basic Science Research, SungKyunKwan University, Suwon 440-746, Korea
| | - C M Varma
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - X J Zhou
- National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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20
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Mansart B, Lorenzana J, Mann A, Odeh A, Scarongella M, Chergui M, Carbone F. Coupling of a high-energy excitation to superconducting quasiparticles in a cuprate from coherent charge fluctuation spectroscopy. Proc Natl Acad Sci U S A 2013; 110:4539-4544. [PMCID: PMC3606993 DOI: 10.1073/pnas.1218742110] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2024] Open
Abstract
Dynamical information on spin degrees of freedom of proteins or solids can be obtained by NMR and electron spin resonance. A technique with similar versatility for charge degrees of freedom and their ultrafast correlations could move the understanding of systems like unconventional superconductors forward. By perturbing the superconducting state in a high-T c cuprate, using a femtosecond laser pulse, we generate coherent oscillations of the Cooper pair condensate that can be described by an NMR/electron spin resonance formalism. The oscillations are detected by transient broad-band reflectivity and are found to resonate at the typical scale of Mott physics (2.6 eV), suggesting the existence of a nonretarded contribution to the pairing interaction, as in unconventional (non-Migdal–Eliashberg) theories.
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Affiliation(s)
- Barbara Mansart
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, and
- Laboratory of Ultrafast Spectroscopy, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; and
| | - José Lorenzana
- Institute for Complex Systems–Consiglio Nazionale delle Ricerche, and Physics Department, University of Rome “La Sapienza,” I-00185 Rome, Italy
| | - Andreas Mann
- Laboratory for Ultrafast Microscopy and Electron Scattering, Institute of Condensed Matter Physics, and
| | - Ahmad Odeh
- Laboratory of Ultrafast Spectroscopy, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; and
| | - Mariateresa Scarongella
- Laboratory of Ultrafast Spectroscopy, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; and
| | - Majed Chergui
- Laboratory of Ultrafast Spectroscopy, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; and
| | - Fabrizio Carbone
- Laboratory of Ultrafast Spectroscopy, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; and
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21
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Thomale R, Platt C, Hanke W, Bernevig BA. Mechanism for explaining differences in the order parameters of FeAs-based and FeP-based pnictide superconductors. PHYSICAL REVIEW LETTERS 2011; 106:187003. [PMID: 21635121 DOI: 10.1103/physrevlett.106.187003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 05/12/2010] [Indexed: 05/30/2023]
Abstract
We put forward a scenario that explains the difference between the order-parameter character in arsenide (As) and phosphorous (P) iron-based superconductors. Using functional renormalization group to analyze it in detail, we find that nodal superconductivity on the electron pockets (hole pocket gaps are always nodeless) can naturally appear when the hole pocket at (π,π) in the unfolded Brillouin zone is absent, as is the case in LaOFeP. There, electron-electron interactions render the gap on the electron pockets softly nodal (of s(±) form). When the pocket of d(xy) orbital character is present, intraorbital interactions with the d(xy) part of the electron Fermi surface drives the superconductivity nodeless.
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Affiliation(s)
- Ronny Thomale
- Department of Physics, Princeton University, New Jersey 08544, USA
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22
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Ahmadi O, Coffey L, Zasadzinski JF, Miyakawa N, Ozyuzer L. Eliashberg analysis of tunneling experiments: support for the pairing glue hypothesis in cuprate superconductors. PHYSICAL REVIEW LETTERS 2011; 106:167005. [PMID: 21599405 DOI: 10.1103/physrevlett.106.167005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Indexed: 05/30/2023]
Abstract
Evidence for the validity of the pairing glue interpretation of high temperature superconductivity is presented using a modified Eliashberg analysis of experimental superconductor-insulator-superconductor (SIS) tunneling data in B2Sr2CaCu2O8 (Bi2212) over a wide range of doping. This is accomplished by extracting detailed information on the diagonal and anomalous contributions to the quasiparticle self-energy. In particular, a comparison of the imaginary part of the anomalous self-energy ImΦ(ω) and the pairing glue spectral function α2F(ω) used in the model is consistent with Hubbard model simulations in the literature. In addition, the real part of the diagonal self-energy for optimal doped Bi2212 bears a strong resemblance to that obtained from photoemission experiments.
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Affiliation(s)
- O Ahmadi
- Physics Department, Illinois Institute of Technology, Chicago, Illinois 60616, USA
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23
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Zhu L, Zhu JX. Superconducting pairing of interacting electrons: implications from the two-impurity Anderson model. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/273/1/012068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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Moreira IDPR, Rivero P, Illas F. Electronic structure of HgBa2Can−1CunO2n+2 (n = 1, 2, 3) superconductor parent compounds from periodic hybrid density functional theory. J Chem Phys 2011; 134:074709. [DOI: 10.1063/1.3553259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ibério de P R Moreira
- Departament de Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Barcelona, Spain
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25
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Chiesa S, Varney CN, Rigol M, Scalettar RT. Magnetism and pairing of two-dimensional trapped fermions. PHYSICAL REVIEW LETTERS 2011; 106:035301. [PMID: 21405279 DOI: 10.1103/physrevlett.106.035301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 11/08/2010] [Indexed: 05/30/2023]
Abstract
The emergence of local phases in a trapped two-component Fermi gas in an optical lattice is studied using quantum Monte Carlo simulations. We treat temperatures that are comparable to or lower than those presently achievable in experiments and large enough systems that both magnetic and paired phases can be detected by inspection of the behavior of suitable short-range correlations. We use the latter to suggest the interaction strength and temperature range at which experimental observation of incipient magnetism and d-wave pairing are more likely and evaluate the relation between entropy and temperature in two-dimensional confined fermionic systems.
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Affiliation(s)
- Simone Chiesa
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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26
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Savini G, Ferrari AC, Giustino F. First-principles prediction of doped graphane as a high-temperature electron-phonon superconductor. PHYSICAL REVIEW LETTERS 2010; 105:037002. [PMID: 20867792 DOI: 10.1103/physrevlett.105.037002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Indexed: 05/29/2023]
Abstract
We predict by first-principles calculations that p-doped graphane is an electron-phonon superconductor with a critical temperature above the boiling point of liquid nitrogen. The unique strength of the chemical bonds between carbon atoms and the large density of electronic states at the Fermi energy arising from the reduced dimensionality give rise to a giant Kohn anomaly in the optical phonon dispersions and push the superconducting critical temperature above 90 K. As evidence of graphane was recently reported, and doping of related materials such as graphene, diamond, and carbon nanostructures is well established, superconducting graphane may be feasible.
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Affiliation(s)
- G Savini
- Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, United Kingdom
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27
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Civelli M. Evolution of the dynamical pairing across the phase diagram of a strongly correlated high-temperature superconductor. PHYSICAL REVIEW LETTERS 2009; 103:136402. [PMID: 19905530 DOI: 10.1103/physrevlett.103.136402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2008] [Indexed: 05/28/2023]
Abstract
We study the dynamics of the Cooper pairing across the T = 0 phase diagram of the two-dimensional Hubbard model, relevant for high-temperature superconductors, using a cluster extension of dynamical mean-field theory. We find that the superconducting pairing function evolves from an unconventional form in the overdoped region into a more conventional boson-mediated retarded form in the underdoped region of the phase diagram. The boson, however, promotes the rise of a pseudogap in the electron density of states rather than a superconducting gap as in the standard theory of superconductivity. We discuss our results in terms of Mott-related phenomena, and we show that they can be observed in tunneling experiments.
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Affiliation(s)
- M Civelli
- Theory Group, Institut Laue Langevin, 38042 Grenoble Cedex, France
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28
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29
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Yang J, Hwang J, Schachinger E, Carbotte JP, Lobo RPSM, Colson D, Forget A, Timusk T. Exchange boson dynamics in cuprates: optical conductivity of HgBa_2CuO_4+delta. PHYSICAL REVIEW LETTERS 2009; 102:027003. [PMID: 19257311 DOI: 10.1103/physrevlett.102.027003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Indexed: 05/27/2023]
Abstract
The electron-boson spectral density function I;{2}chi(Omega) responsible for carrier scattering of the high temperature superconductor HgBa_{2}CuO_{4+delta} (T_{c}=90 K) is calculated from new data on the optical scattering rate. A maximum entropy technique is used. Published data on HgBa_{2}Ca_{2}Cu_{3}O_{8+delta} (T_{c}=130 K) are also inverted and these new results are put in the context of other known cases. All spectra (with two notable exceptions) show a peak at an energy (Omega_{r}) proportional to the superconducting transition temperature Omega_{r} approximately 6.3k_{B}T_{c}. This charge channel relationship follows closely the magnetic resonance seen by polarized neutron scattering, Omega_{r};{neutron} approximately 5.4k_{B}T_{c}. The amplitudes of both peaks decrease strongly with increasing temperature. In some cases, the peak at Omega_{r} is weak and the spectrum can have additional maxima and a background extending up to several hundred meV.
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Affiliation(s)
- J Yang
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada
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30
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Mishchenko AS. Electron - phonon coupling in underdoped high-temperature superconductors. ACTA ACUST UNITED AC 2009. [DOI: 10.3367/ufnr.0179.200912b.1259] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Direct role of structural dynamics in electron-lattice coupling of superconducting cuprates. Proc Natl Acad Sci U S A 2008; 105:20161-6. [PMID: 19095796 DOI: 10.1073/pnas.0811335106] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The mechanism of electron pairing in high-temperature superconductors is still the subject of intense debate. Here, we provide direct evidence of the role of structural dynamics, with selective atomic motions (buckling of copper-oxygen planes), in the anisotropic electron-lattice coupling. The transient structures were determined using time-resolved electron diffraction, following carrier excitation with polarized femtosecond heating pulses, and examined for different dopings and temperatures. The deformation amplitude reaches 0.5% of the c axis value of 30 A when the light polarization is in the direction of the copper-oxygen bond, but its decay slows down at 45 degrees. These findings suggest a selective dynamical lattice involvement with the anisotropic electron-phonon coupling being on a time scale (1-3.5 ps depending on direction) of the same order of magnitude as that of the spin exchange of electron pairing in the high-temperature superconducting phase.
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Maier TA, Poilblanc D, Scalapino DJ. Dynamics of the pairing interaction in the hubbard and t-J models of high-temperature superconductors. PHYSICAL REVIEW LETTERS 2008; 100:237001. [PMID: 18643535 DOI: 10.1103/physrevlett.100.237001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Indexed: 05/26/2023]
Abstract
The question of whether one should speak of a "pairing glue" in the Hubbard and t-J models is basically a question about the dynamics of the pairing interaction. If the dynamics of the pairing interaction arises from virtual states, whose energies correspond to the Mott gap, and give rise to the exchange coupling J, the interaction is instantaneous on the relative time scales of interest. In this case, while one might speak of an "instantaneous glue," this interaction differs from the traditional picture of a retarded pairing interaction. However, as we will show, the dominant contribution to the pairing interaction for both of these models arises from energies reflecting the spectrum seen in the dynamic spin susceptibility. In this case, the basic interaction is retarded, and one speaks of a spin-fluctuation glue which mediates the d-wave pairing.
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Affiliation(s)
- T A Maier
- Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6494, USA.
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Pasupathy AN, Pushp A, Gomes KK, Parker CV, Wen J, Xu Z, Gu G, Ono S, Ando Y, Yazdani A. Electronic Origin of the Inhomogeneous Pairing Interaction in the High-
T
c
Superconductor Bi
2
Sr
2
CaCu
2
O
8+δ. Science 2008; 320:196-201. [PMID: 18403704 DOI: 10.1126/science.1154700] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Abhay N. Pasupathy
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Aakash Pushp
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Kenjiro K. Gomes
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Colin V. Parker
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Jinsheng Wen
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Zhijun Xu
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Genda Gu
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Shimpei Ono
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Yoichi Ando
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Ali Yazdani
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
- Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
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Niestemski FC, Kunwar S, Zhou S, Li S, Ding H, Wang Z, Dai P, Madhavan V. A distinct bosonic mode in an electron-doped high-transition-temperature superconductor. Nature 2007; 450:1058-61. [PMID: 18075588 DOI: 10.1038/nature06430] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Accepted: 10/18/2007] [Indexed: 11/09/2022]
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