Role of hybridization in the superconducting properties of an extended d–p Hubbard model: a detailed numerical study

Abstract

The Roth's two-pole approximation has been used by the present authors to study the effects of the hybridization in the superconducting properties of a strongly correlated electron system. The model used is the extended Hubbard model which includes the d − p hybridization, the p-band and a narrow d-band. The present work is an extension of the previous Ref. [3]. Nevertheless, some important correlation functions necessary to estimate the Roth's band shift, are included together with the temperature T and the Coulomb interaction U to describe the superconductivity. The superconducting order parameter of a cuprate system, is obtained following Beenen and Edwards formalism. Here, we investigate in detail the change of the order parameter associated to temperature, Coulomb interaction and Roth's band shift effects on superconductivity. The phase diagram with Tc versus the total occupation numbers nT , shows the difference respect to the previous work.

Compressibility of a two-dimensional extended Hubbard model

“…However, although this model gives interesting results, probably, a model which takes into account the hybridization between the d− and p−orbitals can be more adequate to treat these systems [3]. Recently, the present authors have applied the Roth's two-pole approximation [4] to study the effects of d − p hybridization on the superconducting properties of an extended d − p Hubbard model [3,5,6]. The authors followed the factorization procedure proposed by Beneen and Edwards [7] to consider d−wave superconductivity.…”

“…The Roth's band shift W kσ = W d kσ + W pd σ is given in terms of correlation functions which can be evaluated from the obtained Green's functions (see Refs. [3,6]). The W d kσ is given as:…”