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Fermi surface in La-based cuprate superconductors from Compton scattering imaging. Nat Commun 2021; 12:2223. [PMID: 33850119 PMCID: PMC8044246 DOI: 10.1038/s41467-021-22229-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/01/2021] [Indexed: 11/09/2022] Open
Abstract
Compton scattering provides invaluable information on the underlying Fermi surface (FS) and is a powerful tool complementary to angle-resolved photoemission spectroscopy and quantum oscillation measurements. Here we perform high-resolution Compton scattering measurements for La2−xSrxCuO4 with x = 0.08 (Tc = 20 K) at 300 K and 150 K, and image the momentum distribution function in the two-dimensional Brillouin zone. We find that the observed images cannot be reconciled with the conventional hole-like FS believed so far. Instead, our data imply that the FS is strongly deformed by the underlying nematicity in each CuO2 plane, but the bulk FSs recover the fourfold symmetry. We also find an unusually strong temperature dependence of the momentum distribution function, which may originate from the pseudogap formation in the presence of the reconstructed FSs due to the underlying nematicity. Additional measurements for x = 0.15 and 0.30 at 300 K suggest similar FS deformation with weaker nematicity, which nearly vanishes at x = 0.30. Compton scattering provides information on the Fermi surface (FS) hence very useful to understand the electronic structure of high temperature superconductors. Here, Yamase et al. perform Compton scattering measurements on La2−xSrxCuO4 samples and observe deformed FS in CuO2 plane due to nematicity but recovering fourfold symmetry in bulk FS.
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Sachdev S. Topological order, emergent gauge fields, and Fermi surface reconstruction. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:014001. [PMID: 30210062 DOI: 10.1088/1361-6633/aae110] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This review describes how topological order associated with the presence of emergent gauge fields can reconstruct Fermi surfaces of metals, even in the absence of translational symmetry breaking. We begin with an introduction to topological order using Wegner's quantum [Formula: see text] gauge theory on the square lattice: the topological state is characterized by the expulsion of defects, carrying [Formula: see text] magnetic flux. The interplay between topological order and the breaking of global symmetry is described by the non-zero temperature statistical mechanics of classical XY models in dimension D = 3; such models also describe the zero temperature quantum phases of bosons with short-range interactions on the square lattice at integer filling. The topological state is again characterized by the expulsion of certain defects, in a state with fluctuating symmetry-breaking order, along with the presence of emergent gauge fields. The phase diagrams of the [Formula: see text] gauge theory and the XY models are obtained by embedding them in U(1) gauge theories, and by studying their Higgs and confining phases. These ideas are then applied to the single-band Hubbard model on the square lattice. A SU(2) gauge theory describes the fluctuations of spin-density-wave order, and its phase diagram is presented by analogy to the XY models. We obtain a class of zero temperature metallic states with fluctuating spin-density wave order, topological order associated with defect expulsion, deconfined emergent gauge fields, reconstructed Fermi surfaces (with 'chargon' or electron-like quasiparticles), but no broken symmetry. We conclude with the application of such metallic states to the pseudogap phase of the cuprates, and note the recent comparison with numerical studies of the Hubbard model and photoemission observations of the electron-doped cuprates. In a detour, we also discuss the influence of Berry phases, and how they can lead to deconfined quantum critical points: this applies to bosons on the square lattice at half-integer filling, and to quantum dimer models.
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Affiliation(s)
- Subir Sachdev
- Department of Physics, Harvard University, Cambridge, MA 02138, United States of America. Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5, Canada. Department of Physics, Stanford University, Stanford, CA 94305, United States of America
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Chatterjee S, Sachdev S, Scheurer MS. Intertwining Topological Order and Broken Symmetry in a Theory of Fluctuating Spin-Density Waves. PHYSICAL REVIEW LETTERS 2017; 119:227002. [PMID: 29286786 DOI: 10.1103/physrevlett.119.227002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Indexed: 06/07/2023]
Abstract
The pseudogap metal phase of the hole-doped cuprate superconductors has two seemingly unrelated characteristics: a gap in the electronic spectrum in the "antinodal" region of the square lattice Brillouin zone and discrete broken symmetries. We present a SU(2) gauge theory of quantum fluctuations of magnetically ordered states which appear in a classical theory of square lattice antiferromagnets, in a spin-density wave mean field theory of the square lattice Hubbard model, and in a CP^{1} theory of spinons. This theory leads to metals with an antinodal gap and topological order which intertwines with the observed broken symmetries.
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Affiliation(s)
- Shubhayu Chatterjee
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Subir Sachdev
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada N2L 2Y5
| | - Mathias S Scheurer
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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Zhou R, Hirata M, Wu T, Vinograd I, Mayaffre H, Krämer S, Horvatić M, Berthier C, Reyes AP, Kuhns PL, Liang R, Hardy WN, Bonn DA, Julien MH. Quasiparticle Scattering off Defects and Possible Bound States in Charge-Ordered YBa_{2}Cu_{3}O_{y}. PHYSICAL REVIEW LETTERS 2017; 118:017001. [PMID: 28106424 DOI: 10.1103/physrevlett.118.017001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Indexed: 06/06/2023]
Abstract
We report the NMR observation of a skewed distribution of ^{17}O Knight shifts when a magnetic field quenches superconductivity and induces long-range charge-density-wave (CDW) order in YBa_{2}Cu_{3}O_{y}. This distribution is explained by an inhomogeneous pattern of the local density of states N(E_{F}) arising from quasiparticle scattering off, yet unidentified, defects in the CDW state. We argue that the effect is most likely related to the formation of quasiparticle bound states, as is known to occur, under specific circumstances, in some metals and superconductors (but not in the CDW state, in general, except for very few cases in 1D materials). These observations should provide insight into the microscopic nature of the CDW, especially regarding the reconstructed band structure and the sensitivity to disorder.
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Affiliation(s)
- R Zhou
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - M Hirata
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - T Wu
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - I Vinograd
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - H Mayaffre
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - S Krämer
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - M Horvatić
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - C Berthier
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-UPS-INSA-EMFL, 38042 Grenoble, France
| | - A P Reyes
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - P L Kuhns
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - R Liang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Canadian Institute for Advanced Research, Toronto M5G 1Z8, Canada
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Canadian Institute for Advanced Research, Toronto M5G 1Z8, Canada
| | - D A Bonn
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Canadian Institute for Advanced Research, Toronto M5G 1Z8, Canada
| | - M-H Julien
- Laboratoire National des Champs Magnétiques Intenses, CNRS-Université Grenoble Alpes-EMFL, 38042 Grenoble, France
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