Heuristic model for slow relaxation of excess conductance in electron glasses

We discuss relaxation of excess conductance ΔG observed in recent experiments on electron glasses. Using a simple model based on some salient features of a hopping system with interactions, we show that for relatively short times ΔG scales like ln(t) and it becomes faster than that as time evolves. The crossover to a faster than ln(t) dependence occurs when wₘᵢₙt≈1, where wₘᵢₙ is the smallest relaxation rate in the system, and t is the observation time.