Configuration space in electron glasses

Abstract

We study numerically the configuration space at low energy 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 smaller for Coulomb glasses than for short-range systems, which in turn is smaller than for non– interacting systems. We analyze 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 system size for long range interactions, while it is basically constant for a short-range interaction. Finally we calculate the density of metastable configurations, i.e. valleys, classified according to their degree of stability.