Paraconductivity of pseudogapped superconductors
We calculate Aslamazov-Larkin paraconductity σAL(T) for a model of strongly disordered superconductors (dimensions d=2,3) with a large pseudogap whose magnitude strongly exceeds transition temperature Tc. We show that, within Gaussian approximation over Cooper-pair fluctuations, paraconductivity is just twice larger that the classical AL result at the same ε = (T-Tc)/Tc. Upon decreasing ε, Gaussian approximation is violated due to local fluctuations of pairing fields that become relevant at ε < ε1 << 1. Characteristic scale ε1 is much larger than the width ε2 of the thermodynamical critical region, that is determined via the Ginzburg criterion, ε2 ≃ ε1d. We argue that in the intermediate region ε2 < ε < ε1 paraconductivity follows the same AL power law, albeit with another (yet unknown) numerical prefactor. At further decrease of the temperature, all kinds of fluctuational corrections become strong at ε < ε2; in particular, conductivity occurs to be strongly inhomogeneous in real space.