ANISOTROPIC SUPERCONDUCTIVITY IN THE 2-DIMENSIONAL HUBBARD-MODEL

We address the problem of anisotropic superconductivity in the two-dimensional Hubbard model. The Eliashberg equations have been generalized to the case which accounts for the anisotropy of the order parameter. Strong local correlations are treated within the mean field slave boson approximation. The superconducting transition temperature T-c is evaluated as a function of the occupation number. Our results indicate that the d-wave state is the most likely channel for superconductivity for small concentration of holes. We have also derived an approximate analytical formula for T-c valid for any value of the occupation number. In addition, the influence of strong correlations on the electron-phonon coupling function is also discussed.