Phase separation instabilities and modulated coherent pairing states in Bi-based cuprates

ORAL

Abstract

There is growing evidence that the unconventional spatial inhomogeneities and structural changes in the doped high-Tc superconductors are accompanied by the pairing of electrons, subsequent quantum phase transitions (QPTs), and condensation in coherent states. We show that these superconducting coherent pairing with mediated opposite spin coupling are driven by phase separation instabilities near the quantum critical points. We examine electron coherent and incoherent pairing instabilities using our results on exact diagonalization in pyramidal and octahedron Hubbard-like clusters under variation of chemical potential (or doping), interaction strength, temperature and magnetic field. We also evaluate the behavior of the energy gap in the vicinity of its sign change in a real space as a function of out-of-plane position of the apical oxygen atom, due to vibration of apical atom and variation of inter-site coupling. Our results show direct correlation between the size of the energy gap characterizing the coherent superconducting state and a modulation of the structural positions of apical atom. These results provide a transparent microscopic explanation of (electron correlation induced) supermodulation of the coherent pairing gap observed recently in scanning tunneling microscopy.

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Authors

  • Armen Kocharian

    California State University, Los Angeles

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department

  • Nilgun Sungar

    Department of Physics and Astronomy, University of California, Irvine, University of California, Irvine, California State University, Fresno, Physics Department, University of California, Santa Cruz, CA, 95064, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, Seogang University, Pohang University of Science \& Technology, UC Santa Cruz, Trinity College, Hartford, Los Alamos National Laboratory, University of Connecticut, Storrs, CSU Long Beach, Physics/Hokkaido University, Japan, Physics/University of California, San Deigo, Physics/California State University, Fresno, CSU Stanislaus, University of California, Santa Barbara, Instituted of Astronomy, University of Cambridge, UK, Max-Planck Institute for Radio Astronomy, Bonn, Germany, Institute of Astronomy, University of Cambridge, UK, California Polytechnic State University, San Luis Obispo, SpaceX, Northrop-Grumman, Cal Poly San Luis Obispo, Department of Physics, University of California at Davis, Davis 95616, United States Department of Agriculture-Agriculture Research Service, Chemistry/California State University Fresno, Physics/California State University Fresno, University of California Santa Barbara, University of California Merced, UC Merced, Stanford University, New Economic School, California Polytechnic State University San Luis Obispo, Indiana University - Purdue University Indianapolis, California Polytechnic State University, San Luis Obispo, Chair of the Physics Department