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Gozlinski T, Henn M, Wolf T, Le Tacon M, Schmalian J, Wulfhekel W. Bosonic excitation spectra of superconductingBi2Sr2CaCu2O8+δandYBa2Cu3O6+xextracted from scanning tunneling spectra. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:175601. [PMID: 38194720 DOI: 10.1088/1361-648x/ad1ca8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/09/2024] [Indexed: 01/11/2024]
Abstract
A detailed interpretation of scanning tunneling spectra obtained on unconventional superconductors enables one to gain information on the pairing boson. Decisive for this approach are inelastic tunneling events. Due to the lack of momentum conservation in tunneling from or to the sharp tip, those are enhanced in the geometry of a scanning tunneling microscope compared to planar tunnel junctions. This work extends the method of obtaining the bosonic excitation spectrum by deconvolution from tunneling spectra to nodald-wave superconductors. In particular, scanning tunneling spectra of slightly underdopedBi2Sr2CaCu2O8+δwith aTcof 82 K and optimally dopedYBa2Cu3O6+xwith aTcof 92 K reveal a resonance mode in their bosonic excitation spectrum atΩres≈63 meVandΩres≈61 meVrespectively. In both cases, the overall shape of the bosonic excitation spectrum is indicative of predominant spin scattering with a resonant mode atΩres<2Δand overdamped spin fluctuations for energies larger than 2Δ. To perform the deconvolution of the experimental data, we implemented an efficient iterative algorithm that significantly enhances the reliability of our analysis.
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Affiliation(s)
- Thomas Gozlinski
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Mirjam Henn
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Thomas Wolf
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
| | - Matthieu Le Tacon
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
| | - Jörg Schmalian
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
- Institute for Theory of Condensed Matter, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Wulf Wulfhekel
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
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2
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Violation of the Time-Reversal and Particle-Hole Symmetries in Strongly Correlated Fermi Systems: A Review. Symmetry (Basel) 2020. [DOI: 10.3390/sym12101596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this review, we consider the time reversal T and particle-antiparticle C symmetries that, being most fundamental, can be violated at microscopic level by a weak interaction. The notable example here is from condensed matter, where strongly correlated Fermi systems like heavy-fermion metals and high Tc superconductors exhibit C and T symmetries violation due to so-called non-Fermi liquid (NFL) behavior. In these systems, tunneling differential conductivity (or resistivity) is a very sensitive tool to experimentally test the above symmetry break. When a strongly correlated Fermi system turns out to be near the topological fermion condensation quantum phase transition (FCQPT), it exhibits the NFL properties, so that the C symmetry breaks down, making the differential tunneling conductivity to be an asymmetric function of the bias voltage V. This asymmetry does not take place in normal metals, where Landau Fermi liquid (LFL) theory holds. Under the application of magnetic field, a heavy fermion metal transits to the LFL state, and σ(V) becomes symmetric function of V. These findings are in good agreement with experimental observations. We suggest that the same topological FCQPT underlies the baryon asymmetry in the Universe. We demonstrate that the most fundamental features of the nature are defined by its topological and symmetry properties.
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3
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Chen FC, Fei Y, Li SJ, Wang Q, Luo X, Yan J, Lu WJ, Tong P, Song WH, Zhu XB, Zhang L, Zhou HB, Zheng FW, Zhang P, Lichtenstein AL, Katsnelson MI, Yin Y, Hao N, Sun YP. Temperature-Induced Lifshitz Transition and Possible Excitonic Instability in ZrSiSe. PHYSICAL REVIEW LETTERS 2020; 124:236601. [PMID: 32603145 DOI: 10.1103/physrevlett.124.236601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/06/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
The nodal-line semimetals have attracted immense interest due to the unique electronic structures such as the linear dispersion and the vanishing density of states as the Fermi energy approaching the nodes. Here, we report temperature-dependent transport and scanning tunneling microscopy (spectroscopy) [STM(S)] measurements on nodal-line semimetal ZrSiSe. Our experimental results and theoretical analyses consistently demonstrate that the temperature induces Lifshitz transitions at 80 and 106 K in ZrSiSe, which results in the transport anomalies at the same temperatures. More strikingly, we observe a V-shaped dip structure around Fermi energy from the STS spectrum at low temperature, which can be attributed to co-effect of the spin-orbit coupling and excitonic instability. Our observations indicate the correlation interaction may play an important role in ZrSiSe, which owns the quasi-two-dimensional electronic structures.
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Affiliation(s)
- F C Chen
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Y Fei
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - S J Li
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- College of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
| | - Q Wang
- University of Science and Technology of China, Hefei 230026, China
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - X Luo
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - J Yan
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - W J Lu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - P Tong
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - W H Song
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - X B Zhu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - L Zhang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - H B Zhou
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - F W Zheng
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - P Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China
| | - A L Lichtenstein
- Institute for Theoretical Physics, University Hamburg, Jungiusstrasse 9, D-20355 Hamburg, Germany
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
| | - M I Katsnelson
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
- Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, NL-6525AJ Nijmegen, The Netherlands
| | - Y Yin
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Center of Microstructures, Nanjing University, Nanjing 210093, China
| | - Ning Hao
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Y P Sun
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- Collaborative Innovation Center of Microstructures, Nanjing University, Nanjing 210093, China
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4
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Wang X, Yuan Y, Xue QK, Li W. Charge ordering in high-temperature superconductors visualized by scanning tunneling microscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:013002. [PMID: 31487703 DOI: 10.1088/1361-648x/ab41c5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Since the discovery of stripe order in La1.6-x Nd0.4Sr x CuO4 superconductors in 1995, charge ordering in cuprate superconductors has been intensively studied by various experimental techniques. Among these studies, scanning tunneling microscope (STM) plays an irreplaceable role in determining the real space structures of charge ordering. STM imaging of different families of cuprates over a wide range of doping levels reveal similar checkerboard-like patterns, indicating that such a charge ordered state is likely a ubiquitous and intrinsic characteristic of cuprate superconductors, which may shed light on understanding the mechanism of high-temperature superconductivity. In another class of high-temperature superconductors, iron-based superconductors, STM studies reveal several charge ordered states as well, but their real-space patterns and the interplay with superconductivity are markedly different among different materials. In this paper, we present a brief review on STM studies of charge ordering in these two classes of high-temperature superconductors. Possible origins of charge ordering and its interplay with superconductivity will be discussed.
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Affiliation(s)
- Xintong Wang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China. Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China
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5
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da Silva Neto EH, Aynajian P, Frano A, Comin R, Schierle E, Weschke E, Gyenis A, Wen J, Schneeloch J, Xu Z, Ono S, Gu G, Le Tacon M, Yazdani A. Ubiquitous interplay between charge ordering and high-temperature superconductivity in cuprates. Science 2013; 343:393-6. [PMID: 24356110 DOI: 10.1126/science.1243479] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Besides superconductivity, copper-oxide high-temperature superconductors are susceptible to other types of ordering. We used scanning tunneling microscopy and resonant elastic x-ray scattering measurements to establish the formation of charge ordering in the high-temperature superconductor Bi2Sr2CaCu2O(8+x). Depending on the hole concentration, the charge ordering in this system occurs with the same period as those found in Y-based or La-based cuprates and displays the analogous competition with superconductivity. These results indicate the similarity of charge organization competing with superconductivity across different families of cuprates. We observed this charge ordering to leave a distinct electron-hole asymmetric signature (and a broad resonance centered at +20 milli-electron volts) in spectroscopic measurements, indicating that it is likely related to the organization of holes in a doped Mott insulator.
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Affiliation(s)
- Eduardo H da Silva Neto
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA
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6
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Marchetti PA, Gambaccini M. Gauge approach to the 'pseudogap' phenomenology of the spectral weight in high Tc cuprates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:475601. [PMID: 23103555 DOI: 10.1088/0953-8984/24/47/475601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We assume the t-t'-J model to describe the CuO(2) planes of hole-doped cuprates and we adapt the spin-charge gauge approach, previously developed for the t-J model, to describe the holes in terms of a spinless fermion carrying the charge (holon) and a neutral boson carrying spin 1/2 (spinon), coupled by a slave-particle gauge field. In this framework we consider the effects of a finite density of incoherent holon pairs in the normal state. Below a crossover temperature, identified as the experimental 'upper pseudogap', the scattering of the 'quanta' of the phase of the holon-pair field against holons reproduces the phenomenology of nodal Fermi arcs coexisting with a gap in the antinodal region. We thus obtain a microscopic derivation of the main features of the hole spectra due to the pseudogap. This result is obtained through a holon Green function which follows naturally from the formalism and analytically interpolates between a Fermi liquid-like and a d-wave superconductor behaviour as the coherence length of the holon-pair order parameter increases. By inserting the gauge coupling with the spinon we construct explicitly the hole Green function and calculate its spectral weight and the corresponding density of states. So we prove that the formation of holon pairs induces a depletion of states on the hole Fermi surface. We compare our results with ARPES and tunnelling experimental data. In our approach the hole preserves a finite Fermi surface until the superconducting transition, where it reduces to four nodes. Therefore we propose that the gap seen in the normal phase of cuprates is due to the thermal broadening of the SC-like peaks masking the Fermi-liquid peak in the spectral weight. The Fermi arcs then correspond to the region of the Fermi surface where the Fermi-liquid peak is unmasked.
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Affiliation(s)
- P A Marchetti
- Dipartimento di Fisica e Astronomia, Università di Padova and INFN, I-35131 Padova, Italy.
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7
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Shastry BS. Dynamical particle-hole asymmetry in high-temperature cuprate superconductors. PHYSICAL REVIEW LETTERS 2012; 109:067004. [PMID: 23006297 DOI: 10.1103/physrevlett.109.067004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Indexed: 06/01/2023]
Abstract
Motivated by the form of recent theoretical results, a quantitative test for an important dynamical particle-hole asymmetry of the electron spectral function at low energies and long wavelengths is proposed. The test requires the decomposition of the angle resolved photo emission intensity, after a specific Fermi symmetrization, into odd and even parts to obtain its ratio R. A large magnitude R is implied in recent theoretical fits at optimal doping around the chemical potential, and I propose that this large asymmetry needs to be checked more directly and thoroughly. This processing requires a slightly higher precision determination of the Fermi momentum relative to current availability.
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Affiliation(s)
- B Sriram Shastry
- Department of Physics, University of California, Santa Cruz, California 95064, USA
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8
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Phillabaum B, Carlson E, Dahmen K. Spatial complexity due to bulk electronic nematicity in a superconducting underdoped cuprate. Nat Commun 2012; 3:915. [DOI: 10.1038/ncomms1920] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 05/18/2012] [Indexed: 11/09/2022] Open
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9
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Yang KY, Huang K, Chen WQ, Rice TM, Zhang FC. Andreev and single-particle tunneling spectra of underdoped cuprate superconductors. PHYSICAL REVIEW LETTERS 2010; 105:167004. [PMID: 21230999 DOI: 10.1103/physrevlett.105.167004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 07/27/2010] [Indexed: 05/30/2023]
Abstract
We study tunneling spectroscopy between a normal metal and an underdoped cuprate superconductor modeled by a phenomenological theory in which the pseudogap is a precursor to the undoped Mott insulator. In the low barrier tunneling limit, the spectra are enhanced by Andreev reflection only within a voltage region of the small superconducting energy gap. In the high barrier tunneling limit, the spectra show a large energy pseudogap associated with single particle tunneling. Our theory semiquantitatively describes the two gap behavior observed in tunneling experiments.
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Affiliation(s)
- Kai-Yu Yang
- Institut fr Theoretische Physik, ETH Zrich, CH-8093 Zrich, Switzerland
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10
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Yazdani A. Visualizing pair formation on the atomic scale and the search for the mechanism of superconductivity in high-T(c) cuprates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:164214. [PMID: 21825394 DOI: 10.1088/0953-8984/21/16/164214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed several new experimental techniques, based on the scanning tunneling microscope, to visualize the process of pair formation on the atomic scale and to probe with high precision what controls the strength of pairing in high-T(c) cuprate superconductor compounds. These new experiments provide evidence that pairing in these exotic superconductors occurs above the bulk transition temperature and in nanoscale regions with sizes of 1-3 nm. The high temperature nucleation and proliferation of these nanoscale puddles have a strong connection to the temperature-doping phase diagram of these superconductors. On average we have found that the pairing gap Δ and the temperature at which they first nucleate T(p) follow the simple relation: 2Δ/k(B)T(p)∼8. Moreover, the variations of the pairing strength on the nanoscale can be examined to find microscopic clues to the mechanism of pairing. Specifically, we have found evidence that suggests that strong electronic correlation, as opposed to coupling of electrons to bosons, is responsible for the pairing mechanism in the cuprates. Surprisingly, we have found that nanoscale measurements of electronic correlations in the normal state (at temperatures as high as twice T(c)) can be used to predict the strength of the local pairing interaction at low temperatures.
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Affiliation(s)
- A Yazdani
- Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08540, USA
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11
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Nieminen J, Lin H, Markiewicz RS, Bansil A. Origin of the electron-hole asymmetry in the scanning tunneling spectrum of the high-temperature Bi2Sr2CaCu2O8+delta superconductor. PHYSICAL REVIEW LETTERS 2009; 102:037001. [PMID: 19257381 DOI: 10.1103/physrevlett.102.037001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2008] [Indexed: 05/27/2023]
Abstract
We have developed a material specific theoretical framework for modeling scanning tunneling spectroscopy (STS) of high-temperature superconducting materials in the normal as well as the superconducting state. Results for Bi2Sr2CaCu2O8+delta (Bi2212) show clearly that the tunneling process strongly modifies the STS spectrum from the local density of states of the dx2-y2 orbital of Cu. The dominant tunneling channel to the surface Bi involves the dx2-y2 orbitals of the four neighboring Cu atoms. In accord with experimental observations, the computed spectrum displays a remarkable asymmetry between the processes of electron injection and extraction, which arises from contributions of Cu dz2 and other orbitals to the tunneling current.
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Affiliation(s)
- Jouko Nieminen
- Institute of Physics, Tampere University of Technology, P.O. Box 692, 33101 Tampere, Finland.
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12
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de Castro GL, Berthod C, Piriou A, Giannini E, Fischer Ø. Preeminent role of the van Hove singularity in the strong-coupling analysis of scanning tunneling spectroscopy for two-dimensional cuprate superconductors. PHYSICAL REVIEW LETTERS 2008; 101:267004. [PMID: 19437664 DOI: 10.1103/physrevlett.101.267004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In two dimensions the noninteracting density of states displays a van Hove singularity (VHS) which introduces an intrinsic electron-hole asymmetry, absent in three dimensions. We show that due to this VHS the strong-coupling analysis of tunneling spectra in high-Tc superconductors must be reconsidered. Based on a microscopic model which reproduces the experimental data with excellent accuracy, we elucidate the peculiar role played by the VHS in shaping the tunneling spectra, and show that more conventional analysis of strong-coupling effects can lead to severe errors.
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13
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Tan F, Wang QH. Two-mode variational Monte Carlo study of quasiparticle excitations in cuprate superconductors. PHYSICAL REVIEW LETTERS 2008; 100:117004. [PMID: 18517816 DOI: 10.1103/physrevlett.100.117004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Indexed: 05/26/2023]
Abstract
Recent measurements of quasiparticles in hole-doped cuprates revealed highly unusual features: (i) the doping-independent Fermi velocity, (ii) two energy scales in the quasiparticle spectral function, and (iii) a suppression of the low-energy spectral weight near the zone center. We explain these important facts by a novel two-mode variational Monte Carlo (VMC) study of the t-J model, which resolves a long-standing issue of the sum rule for quasiparticle spectral weights in VMC studies. The electron-doped case is also discussed.
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Affiliation(s)
- Fei Tan
- National Laboratory of Solid State Microstructures & Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
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14
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Yang HY, Li T. Variational study of the one dimensional t-J model: a unified description of the ground state phase diagram. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:186218. [PMID: 21690999 DOI: 10.1088/0953-8984/19/18/186218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We find that the Gutzwiller projected Fermi sea wavefunction (GPWF) has the correct phase structure to describe the kink nature of the doped holes in the ground state of the one dimensional t-J model. We find the residual charge correlation beyond the GPWF is well described by an XXZ-type effective Hamiltonian. A Pfaffian-type variational wavefunction with only one parameter is proposed based on this observation and is found to reproduce correctly the global phase diagram and correlation functions of the one dimensional t-J model in both the Tomonaga-Luttinger regime and the Luther-Emery regime.
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Affiliation(s)
- Hong-Yu Yang
- Center for Advanced Study, Tsinghua University, Beijing 100084, People's Republic of China
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15
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Kohsaka Y, Taylor C, Fujita K, Schmidt A, Lupien C, Hanaguri T, Azuma M, Takano M, Eisaki H, Takagi H, Uchida S, Davis JC. An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates. Science 2007; 315:1380-5. [PMID: 17289939 DOI: 10.1126/science.1138584] [Citation(s) in RCA: 525] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Removing electrons from the CuO2 plane of cuprates alters the electronic correlations sufficiently to produce high-temperature superconductivity. Associated with these changes are spectral-weight transfers from the high-energy states of the insulator to low energies. In theory, these should be detectable as an imbalance between the tunneling rate for electron injection and extraction-a tunneling asymmetry. We introduce atomic-resolution tunneling-asymmetry imaging, finding virtually identical phenomena in two lightly hole-doped cuprates: Ca(1.88)Na(0.12)CuO(2)Cl2 and Bi2Sr2Dy(0.2)Ca(0.8)Cu2O(8+delta). Intense spatial variations in tunneling asymmetry occur primarily at the planar oxygen sites; their spatial arrangement forms a Cu-O-Cu bond-centered electronic pattern without long-range order but with 4a(0)-wide unidirectional electronic domains dispersed throughout (a(0): the Cu-O-Cu distance). The emerging picture is then of a partial hole localization within an intrinsic electronic glass evolving, at higher hole densities, into complete delocalization and highest-temperature superconductivity.
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Affiliation(s)
- Y Kohsaka
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
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16
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Sensarma R, Randeria M, Trivedi N. Can one determine the underlying fermi surface in the superconducting state of strongly correlated systems? PHYSICAL REVIEW LETTERS 2007; 98:027004. [PMID: 17358639 DOI: 10.1103/physrevlett.98.027004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Indexed: 05/14/2023]
Abstract
The question of determining the underlying Fermi surface (FS) that is gapped by superconductivity (SC) is of central importance in strongly correlated systems, particularly in view of angle-resolved photoemission experiments. Here we explore various definitions of the FS in the superconducting state using the zero-energy Green's function, the excitation spectrum, and the momentum distribution. We examine (a) d-wave SC in high-Tc cuprates, and (b) the s-wave superfluid in the BCS-Bose-Einstein condensation (BEC) crossover. In each case we show that the various definitions agree, to a large extent, but all of them violate the Luttinger count and do not enclose the total electron density. We discuss the important role of chemical potential renormalization and incoherent spectral weight in this violation.
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Affiliation(s)
- Rajdeep Sensarma
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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17
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Chen Y, Rice TM, Zhang FC. Rotational symmetry breaking in the ground state of sodium-doped cuprate superconductors. PHYSICAL REVIEW LETTERS 2006; 97:237004. [PMID: 17280234 DOI: 10.1103/physrevlett.97.237004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Indexed: 05/13/2023]
Abstract
We use an extended t-J model to study a single hole bound to a Na+ acceptor in Ca2-xNaxCuO2Cl2. For parameters suitable to cuprates, the ground state has a twofold degeneracy, corresponding to even (odd) reflection symmetry around the x (y) axes. The conductance pattern of the broken symmetry state is anisotropic as the tip of a tunneling microscope scans above the Cu-O-Cu bonds along the x (y) axes. This anisotropy is pronounced at lower voltages but reduced at higher voltages. Our theory agrees qualitatively with recent data of scanning tunneling microscopy showing broken local rotational symmetry.
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Affiliation(s)
- Yan Chen
- Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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18
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Ribeiro TC, Wen XG. Tunneling spectra of layered strongly correlated d-wave superconductors. PHYSICAL REVIEW LETTERS 2006; 97:057003. [PMID: 17026133 DOI: 10.1103/physrevlett.97.057003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Indexed: 05/12/2023]
Abstract
Tunneling conductance experiments on cuprate superconductors exhibit a large diversity of spectra that appear in different nanosized regions of inhomogeneous samples. In this Letter, we use a mean-field approach to the tt't''J model in order to address the features in these spectra that deviate from the BCS paradigm, namely, the bias sign asymmetry at high bias, the generic lack of evidence for the van Hove singularity, and the absence of coherence peaks at low dopings. We conclude that these features can be reproduced in homogeneous layered d-wave superconductors solely due to a proximate Mott insulating transition. We also establish the connection between the above tunneling spectral features and the strong renormalization of the electron dispersion around (0, pi) and (pi, 0) and the momentum space anisotropy of electronic states observed in angle-resolved photoemission spectroscopy experiments.
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Affiliation(s)
- Tiago C Ribeiro
- Department of Physics, University of California, Berkeley, CA 94720, USA
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Edegger B, Muthukumar VN, Gros C, Anderson PW. Electronic structure of strongly correlated d-wave superconductors. PHYSICAL REVIEW LETTERS 2006; 96:207002. [PMID: 16803197 DOI: 10.1103/physrevlett.96.207002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2005] [Indexed: 05/10/2023]
Abstract
We study the electronic structure of a strongly correlated d-wave superconducting state. Combining a renormalized mean field theory with direct calculation of matrix elements, we obtain explicit analytical results for the nodal Fermi velocity upsilon(F), the Fermi wave vector k(F), and the momentum distribution n(k) as a function of hole doping in a Gutzwiller projected d-wave superconductor. We calculate the energy dispersion E(k) and spectral weight of the Gutzwiller-Bogoliubov quasiparticles and find that the spectral weight associated with the quasiparticle excitation at the antinodal point shows a nonmonotonic behavior as a function of doping. Results are compared to angle resolved photoemission spectroscopy of the high-temperature superconductors.
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Affiliation(s)
- Bernhard Edegger
- Institute for Theoretical Physics, Universität Frankfurt, D-60438 Frankfurt, Germany
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