Nonlinear screening theory of the Coulomb glass

TL;DR

This paper develops a nonlinear screening theory to understand gap formation and glassy freezing in Coulomb glasses, revealing that a pseudo-gap appears at high temperatures due to short-range correlations, distinct from the glassy phase.

Contribution

The paper introduces a nonlinear screening framework that explains the emergence of a pseudo-gap at high temperatures independently of disorder, and distinguishes it from the glassy phase pseudo-gap.

Findings

Pseudo-gap begins to form at temperatures comparable to Coulomb energy.

Short-range correlations develop in the plasma phase without disorder.

Glassy ordering occurs at much lower temperatures, following nonlinear screening.

Abstract

A nonlinear screening theory is formulated to study the problem of gap formation and its relation to glassy freezing in classical Coulomb glasses. We find that a pseudo-gap ("plasma dip") in a single-particle density of states begins to open already at temperatures comparable to the Coulomb energy. This phenomenon is shown to reflect the emergence of short range correlations in a liquid (plasma) phase, a process which occurs even in the absence of disorder. Glassy ordering emerges when disorder is present, but this occurs only at temperatures more then an order of magnitude lower, which is shown to follow from nonlinear screening of the Coulomb interaction. Our result suggest that the formation of the "plasma dip" at high temperatures is a process distinct from the formation of the Efros-Shklovskii (ES) pseudo-gap, which in our model emerges only within the glassy phase.