Transition to a microscopic diffusion regime and dimensional crossover in a disordered conductor

Abstract

The low-temperature behaviour of the resistance of indium oxide samples is discussed within the framework of localisation theories. It is demonstrated that, in three dimensions, the interplay between the effective inelastic diffusion length lin and the correlation length xi determines the nature of the diffusion process. A crossover to two-dimensional behaviour is observed once lin becomes comparable with the sample thickness.