Configuration space in electron glasses

Abstract

We study numerically the low-energy configuration space of electron glasses. We consider systems with Coulomb interactions, short-range interactions and no interactions. First, we calculate the integrated density of configurations as a function of energy. At a given energy, this density is lower for Coulomb glasses than for short-range systems, which in turn is lower than for non-interacting systems. We analyse how the site occupancy varies with the number of configurations. Through this study we estimate the number of particles involved in a typical low-energy transition between configurations. This number increases with increasing system size for long-range interactions, while it is basically constant for a short-range interaction. Finally we calculate the density of metastable configurations, that is valleys, classified according to their degree of stability.