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Point Defect Disorder in Models of High Temperature Superconductivity

  • J. W. Halley
  • C. Das Gupta
  • S. Davis
  • X.-F. Wang

Abstract

Experimental high T c systems are intrinsically strongly disordered by point defects. Here we consider two possible consequences of this fact: 1) The magnetic phases of prominent models for high T c are strongly affected. We present numerical calculations of the phase diagram of the Hubbard model as a function of the concentration of point defects and of the band filling in the Hartree Fock approximation. The results may explain the failure to experimentally observe a spin density wave phase predicted by Hartree Fock calculations without defects. 2) The superconductivity of the system may be strongly affected. We consider a model in which the pairing interactions are generated by point defects. We present numerical data on the density of states, T c and local charge density in the BCS approximation, while taking full account of the disorder. The stability of the BCS state was also checked using a variational Monte Carlo calculation.

Keywords

Point Defect Hubbard Model Spin Density Wave Magnetic Phase Diagram Special Bond 
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Copyright information

© Springer Science+Business Media New York 1992

Authors and Affiliations

  • J. W. Halley
    • 1
  • C. Das Gupta
    • 1
    • 2
  • S. Davis
    • 1
    • 3
  • X.-F. Wang
    • 1
  1. 1.School of Physics and AstronomyUniversity of MinnesotaMinneapolisUSA
  2. 2.Indian Institute of ScienceBangaloreIndia
  3. 3.Department of MathematicsCornell UniversityIthacaUSA

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