Off-equilibrium dynamics of the two-dimensional Coulomb glass

– The dynamics of the 2D Coulomb glass model is investigated by kinetic Monte Carlo simulation. An exponential divergence of the relaxation time signals a zero-temperature freezing transition. At low temperatures the dynamics of the system is glassy. The local charge correlations and the response to perturbations of the local potential show aging. The dynamics of formation of the Coulomb gap is slow and the density of states at the Fermi level decays in time as a power law. The relevance of these findings for recent transport experiments in Anderson-insulating films is pointed out. A low-temperature glassy phase that had been anticipated by several authors [1, 2] was recently observed in studies of hopping conduction in disordered InO films [3,4]. The experiments show sluggish, non-exponential, relaxation of the conductance [3] as well as aging and memory effects [4] similar to those observed in glasses [5]. The details of the dependence of the observed effects on carrier density and sample conductance suggests that the glassiness of these systems is associated to the interplay of disorder and electron interactions [4]. The experimental systems, with very low carrier densities and very large resistances, are deep in the Anderson-Mott localized phase. In this regime quantum effects are qualitatively unimportant and a description based on the classical 2D Coulomb glass model is appropriate. The Hamiltonian of the model is [10]