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

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.