Comment on "Density of States and Critical Behavior of the Coulomb Glass"

TL;DR

This paper critically examines previous numerical results on the Coulomb glass, arguing that their conclusions about the density of states and Coulomb gap behavior are based on flawed assumptions and data misinterpretations.

Contribution

It challenges prior claims about the asymptotic behavior of the Coulomb gap and corrects the interpretation of density of states data in the Coulomb glass model.

Findings

Previous simulations are based on unjustified assumptions.

Part of the data shows a broad gap due to instability.

The earlier conclusions about the Coulomb gap are not supported.

Abstract

In a recent numerical investigation of the Coulomb glass, Surer et al. [Phys. Rev. Lett. 102, 067205 (2009)] concluded that their simulation results are consistent with the Efros Shklovskii prediction for the density of states in the three-dimensional case. Here, we show that this statement has no relevance concerning the problem of the asymptotic behavior in the Coulomb gap since it is based on unjustified assumptions. Moreover, for the random-displacement Coulomb glass model, we demonstrate that a part of the density of states data by Surer et al. erroneously exhibit a broad gap. This is related to the staggered occupation being instable contrary to their findings.