Strong-coupling expansions for the anharmonic Holstein model and for the Holstein-Hubbard model
Condensed Matter
2009-10-28 v1
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.
Keywords
Cite
@article{arxiv.cond-mat/9604006,
title = {Strong-coupling expansions for the anharmonic Holstein model and for the Holstein-Hubbard model},
author = {J. K. Freericks and G. D. Mahan},
journal= {arXiv preprint arXiv:cond-mat/9604006},
year = {2009}
}
Comments
34 pages, typeset in ReVTeX, 11 encapsulated postscript files included