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 Δ0 and the superconducting critical temperature Tc 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, Tc diminishes as V increases, and there exist a critical value Vc for which superconductivity is suppressed