Effect of fluctuations on electronic properties above the superconducting transition

A calculation of the microscopic effects of the fluctuations of the superconducting order parameter in the classical region above T_c 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(ω). For a one-dimensional sample, K appears to diverge as ${\left[\frac{(T-T_c)}{T_c}\right]}^{-\frac{1}{2}}$ while for two and three dimensions, K depends weakly on temperature. The behavior of N(ω) 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 ${\left[\frac{(T-T_c)}{T_c}\right]}^{-2}$. The agreement with experiment is satisfactory.