Coulomb gap at finite temperatures

The Coulomb glass, a model of interacting localized electrons in a random potential, exhibits a soft gap, the Coulomb gap, in the single-particle density of states (DOS) g(ɛ,T) close to the chemical potential μ. In this paper we investigate the Coulomb gap at finite temperatures T by means of a Monte Carlo method. We find that the Coulomb gap fills with increasing temperature. In contrast to previous results the temperature dependence is, however, much stronger than g(μ,T)∼${\mathit{T}}^{\mathit{D}\mathrm{-}1}$ as predicted analytically. It can be described by power laws with the exponents 1.75±0.1 for the two-dimensional model and 2.7±0.1 for the three-dimensional model. Nevertheless, the relation g(μ,T)∼g(ɛ,T=0) with ‖ɛ-μ‖=${\mathit{k}}_{\mathit{BT}}$ seems to be valid, since energy dependence of the DOS at low temperatures has also been found to follow power laws with these exponents.