Variable range hopping in the Coulomb glass

TL;DR

This paper investigates the conductance behavior of a two-dimensional Coulomb glass using a mean-field approach, revealing a crossover influenced by electron interactions and validating a scaling relation through simulations.

Contribution

It introduces a Hartree self-consistent method to analyze Coulomb glass conductance, clarifying the physical mechanisms and incorporating interaction-induced correlations and temperature effects.

Findings

Identifies a crossover in conductance regimes due to Coulomb interactions.

Verifies a universal scaling relation for conductance.

Provides a physical picture of electron interactions in localized states.

Abstract

We use a mean-field (Hartree-like) approach to study the conductance of a strongly localized electron system in two dimensions. We find a crossover between a regime where Coulomb interactions modify the conductance significantly to a regime where they are negligible. We show that under rather general conditions the conduction obeys a scaling relation which we verify using numerical simulations. The use of a Hartree self-consistent approach gives a clear physical picture, and removes the ambiguity of the use of single-particle tunneling density-of-states (DOS) in the calculation of the conductance. Furthermore, the theory contains interaction-induced correlations between the on site energy of the localized states and distances, as well as finite temperature corrections of the DOS.