S. Barabash et al., Conductivity due to classical phase fluctuations in a model for high-T-c superconductors, PHYS REV B, 61(22), 2000, pp. R14924-R14927
We consider the real part of the conductivity, sigma(1:alpha alpha)(omega),
arising from classical phase fluctuations in high-T-c superconductors. We
show that integral(0)(infinity)sigma(1:alpha alpha)d omega not equal 0 belo
w the superconducting transition temperature T-c, provided there is some qu
enched disorder in the system. Furthermore, for a fixed amount of quenched
disorder, this integral at low temperatures is proportional to the zero-tem
perature superfluid density, in agreement with experiment. We calculate sig
ma(1:alpha alpha)(omega) explicitly for a model of overdamped phase fluctua
tions.