CURRENT RELAXATION IN DISORDERED CONDUCTORS

Current relaxation in disordered conductors is considered. For noninteracting electrons at zero temperature T=0 relaxation times are shown to fluctuate from sample to sample with the probability of large relaxation times τR being logarithmically normal. The dispersion of log τR diverges at the mobility edge Ec, so that the relaxation becomes very slow at E → Ec. For small samples at T≠0 the time dependent relaxation current exhibits reproducible aperiodic oscillations with the characteristic period being T-1. The averaging of the relaxation current over the time interval is equivalent to the ensemble averaging, both giving rise to logarithmically normal long-time tails of response function. © 1990.