Cumulant expansion for the p-d model

Abstract

We propose a nonstandard perturbative solution of the p-d model, based on a generalized cumulant expansion. Using a temperature-dependent Green's function formalism, the effect of the on-site Coulomb repulsion U is taken into account to determine the density of states of correlated electrons, with varying parameters of the Hamiltonian. A qualitative comparison with similar perturbative approaches is discussed.