EFFECT ON THE SUPERCONDUCTING TEMPERATURE OF THE MOMENTUM DEPENDENCE OF THE ELECTRON-ELECTRON INTERACTION

The pairing interaction V(k-k') is often replaced by a constant V (usually taken to be the average of V(k-k') over the Fermi surface) in the calculation of the superconducting transition temperature T-c in the standard BCS theory. We examine here the effect of an anisotropic momentum dependence in V(k-k') on T-c. We present here results for a model separable interaction containing a parameter that controls the anisotropy. We show that for this model T-c is always larger than the corresponding BCS averaged value.