BCS PAIRING IN A CORRELATED NARROW-BAND METAL

A theoretical study of BCS pairing in an extended Hubbard model with o n-site repulsion (U) and a BCS pairing field (V) is presented. Treatin g the effect of U in the Gutzwiller approximation, we study the effect of increasing U in the Fermi-liquid phase, on the BCS pairing due to V. It is found that the superconducting energy gap (DELTA) is strongly enhanced in the correlated metallic phase near half-filling of the ba nd due to the localization effects of U. Further, the ground state is found to be superconducting even when Absolute value of V < U, contrar y to the prediction in a Hartree-Fock treatment.