Superconductivity in a strongly correlated electron system: A theoretical study

In this work we study the superconductivity within an attractive two-dimensional one-band Hubbard model. We consider a d-wave superconducting gap and a Hubbard-I approximation to describe the strongly correlated superconducting regime. We use the Green's function method to obtain the order parameter Delta and the superconducting critical temperature T-c. The results show that for fixed values of the superconducting attractive potential U (U < 0), the gap increases for low temperatures but diminishes abruptly as the temperature increases. The effect of pressure is discussed, varying the next-nearest-neighbor hopping t(2), yielding a change in T-c, and also in Delta(0), and a tendency to suppress the superconductivity. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3063667]