Suppressed Density of States in Self-Generated Coulomb Glasses

TL;DR

This paper studies self-generated Coulomb glasses and finds they lack marginal stability, exhibiting an exponential soft gap in the density of states, which differs from disordered electron glasses.

Contribution

It introduces a new class of self-generated glasses with suppressed density of states and extends stability criteria to include local charge correlations.

Findings

Absence of marginal stability in self-generated Coulomb glasses

Exponential soft gap in the density of states

Extension of Efros-Shklovskii stability criterion

Abstract

We investigate the structure of metastable states in self-generated Coulomb glasses. In dramatic contrast to disordered electron glasses, we find that these states lack marginal stability. Such absence of marginal stability is reflected by the suppression of the single-particle density of states into an exponentially soft gap of the form $g(\epsilon) \sim e^{-V / \xi |\epsilon|}$. To analytically explain this behavior, we extend the stability criterion of Efros and Shklovskii to incorporate local charge correlations, in qualitative agreement with our numerical findings. Our work suggests the existence of a new class of self-generated glasses dominated by strong geometric frustration.