Effect of fluctuations on electronic properties above the superconducting transition

Abstract

A calculation of the microscopic effects of the fluctuations of the superconducting order parameter in the classical region above Tc on the electron Green's function in dirty materials is presented. The calculation is formulated in the presence of a magnetic field. The results of this calculation in the zero-field limit are used to obtain the change in the thermal conductivity K and in the electron density of states N(). For a one-dimensional sample, K appears to diverge as [(T-Tc)Tc]-12 while for two and three dimensions, K depends weakly on temperature. The behavior of N() is qualitatively similar to that of a gapless superconductor below its transition temperature, although the detailed frequency dependence is different. For thin films, the depression at the Fermi surface increases as [(T-Tc)Tc]-2. The agreement with experiment is satisfactory. © 1970 The American Physical Society.