Specific Heat of Disordered Superconductors Induced by Negative Centers

We show that superconductors with inhomogeneous order parameters can show similar features as anisotropic ones. In this paper we study the low temperature specific heat dependence in such a system and we show that the disorder associated with randomly distributed attractive centers convert the BCS temperature exponential behaviour into a power law formula. To describe superconductivity we used a random version of the negative U Hubbard model, while the disorder was treated by means of the Coherent Potential Approximation (CPA).