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Author Freericks, J. K. ♦ Mahan, G. D.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ ELECTRON-PHONON COUPLING ♦ HUBBARD MODEL ♦ LATTICE VIBRATIONS ♦ ANHARMONIC OSCILLATORS ♦ STRONG-COUPLING MODEL ♦ MEAN-FIELD THEORY ♦ SUPERCONDUCTIVITY ♦ PHASE DIAGRAMS ♦ SERIES EXPANSION
Abstract 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} {ital 1996 The American Physical Society.}
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-10-01
Publisher Department Oak Ridge National Laboratory
Publisher Place United States
Journal Physical Review, B: Condensed Matter
Volume Number 54
Issue Number 13
Organization Oak Ridge National Laboratory


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