Physical Review Letters
Systematic 1/d Corrections to the Infinite-Dimensional Limit of Correlated Lattice Electron Models
Avraham Schiller, Kevin Ingersent
Abstract
We present a self-consistent treatment of Hubbard-like lattice models at large, but finite, spatial dimensions $d$. This involves a systematic expansion in powers of $1/d$ about the limit $d\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\infty}$. The first-order corrections can be obtained by self-consistent solution of coupled one- and two-impurity models. We calculate the leading corrections to properties of the Falicov-Kimball model. The infinite-dimensional limit seems to describe this particular model remarkably well even for $d\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$.