期刊论文详细信息
Strong-coupling expansions for the anharmonic Holstein model and for the Holstein-Hubbard model | |
Article | |
关键词: INFINITE DIMENSIONS; SUPERCONDUCTIVITY; ATTRACTION; SYMMETRY; SYSTEMS; STATE; | |
DOI : 10.1103/PhysRevB.54.9372 | |
来源: SCIE |
【 摘 要 】
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.
【 授权许可】
Free