Published October 1996 | Version v1
Journal article

Strong-coupling expansions for the anharmonic Holstein model and for the Holstein-Hubbard model

  • 1. Department of Physics, Georgetown University, Washington, D.C. 20057-0995 (United States)
  • 2. Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States)
  • 3. Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)

Description

A strong-coupling expansion is applied to the anharmonic Holstein model and to the Holstein-Hubbard model through fourth order in the hopping matrix element. Mean-field theory is then employed to determine transition temperatures of the effective (pseudospin) Hamiltonian. We find that anharmonic effects are not easily mimicked by an on-site Coulomb repulsion and that anharmonicity strongly favors superconductivity relative to charge-density-wave order. Surprisingly, the phase diagram is strongly modified by relatively small values of the anharmonicity. copyright 1996 The American Physical Society

Additional details

Publishing Information

Journal Title
Physical Review. B, Condensed Matter
Journal Volume
54
Journal Issue
13
Journal Page Range
p. 9372-9384.
ISSN
0163-1829
CODEN
PRBMDO