A self-consistent, conserving theory of the attractive Hubbard model in two dimensions

Дата и время публикации : 1998-02-10T17:58:22Z

Авторы публикации и институты :
M. Letz
R. J. Gooding

Ссылка на журнал-издание: J. of Phys. Cond. Mat. 10,(31) 6931-6951 (1998)
Коментарии к cтатье: 13 pages, including 14 figures
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el, cond-mat.supr-con

Краткий обзор статьи: We have investigated the attractive Hubbard model in the low density limit for the 2D square lattice using the ladder approximation for the vertex function in a self-consistent, conserving formulation. In the parameter region where the on-site attraction is of the order of the bandwidth, we found no evidence of a pseudo gap. Further, we have observed that the suppression of the Fermi surface known to destroy superconductivity in one and two dimensions, when these systems are treated using a non self-consistent theory (Schmitt-Rink, et al., Phys. Rev. Lett. 63, 445 (1989)), does not occur when pair-pair interactions are included. However, we do find a quasiparticle lifetime that varies linearly with temperature, similar to many experiments. Thus, although this system has a Fermi surface, it shows non Fermi liquid type behaviour over a wide temperature range. We stress that our work uses thermal Green’s functions along the real time axis, and thus allows for a more accurate determination of the dynamical properties of a model than theories that require extrapolations from the imaginary frequency axis.

Category: Physics