Role of Hybridization in the Superconducting Properties of an Extended $d-p$ Hubbard Model: a Detailed Numerical Study

TL;DR

This study uses Roth's two-pole approximation to analyze how hybridization affects superconductivity in an extended $d-p$ Hubbard model, revealing detailed dependencies on temperature, Coulomb interaction, and band shifts.

Contribution

It extends previous work by including additional correlation functions and analyzing their impact on the superconducting order parameter and phase diagram.

Findings

Hybridization significantly influences the superconducting order parameter.

The phase diagram shows notable differences from previous models.

Temperature and Coulomb interaction critically affect superconductivity.

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 a previous reference [Intern. Journ. of Modern Phys. B, Vol. 18 No. 2 (2004) 241]. 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 $T_c$ versus the total occupation numbers $n_T$, shows the difference respect to the previous work.