Superconductivity and hybridization in a two-dimensional extended Hubbard model: Strong coupling regime

In this work we study the effect of hybridization on the superconductivity within an attractive two-band Hubbard model. We describe the interband effects through an one body mixing term, differently from standard approaches. We consider a s-wave superconducting gap and a Hubbard-I approximation to describe the strongly correlated superconducting regime. We use Greens' function method to obtain the order parameter Delta(0) and the superconducting critical temperature T-c for various values of the hybridization strength V and the attractive potential U. The results show that for fixed values of U and V the gap raises for low temperatures and diminishes abruptly as the temperature increases. Also, T-c diminishes as V increases, and there exist a critical value V-c for which superconductivity is suppressed. (C) 2008 Elsevier B. V. All rights reserved.