The results of a calculation of the properties of a dirty superconductor near the transition temperature are described. The density of states and conductivity are obtained within an approximation that corresponds to BCS theory above $T_c$. In two dimensions or less no singularity is encountered at $T_c$; instead, the conventional BCS results are obtained for $T\ll T_c$, even though the order parameter is strictly zero. The anomalous contribution to the conductivity reported by Maki is found to be well behaved and finite in the absence of external pair breaking.

• Received 31 August 1971

DOI:https://doi.org/10.1103/PhysRevLett.27.1273