A Contribution of the Density-of-states Term to the Paraconductivity in a d-wave Superconductor

A theoretical study is carried out to calculate the density-of-states (DOS) contribution to the paraconductivity(PC) for a d-wave superconductor in the context of our previous d-wave PC approach. Resonant scattering by nonmagnetic impurities is considered under the unitary limit condition in a clean layered superconductor. In calculating the DOS term, we also include consequences ofshort-wavelength fluctuations. It is found that a negative contribution from the DOS term compensates the whole positive Maki-Thompson terms, leaving a small negative contribution depending on the scattering rate. Therefore, the d-wave PC in the absence of impurities is characterized only as the Aslamazov-Larkin contribution, in terms of which experiments in a cupratesuperconductor with the optimal doping could be explained.