Glassy states in fermionic systems with strong disorder and interactions

TL;DR

This paper investigates how strong disorder and interactions influence the electronic states in two-dimensional fermionic systems, revealing that disorder can destroy the Mott gap and lead to a glassy state characterized by universal scaling behavior.

Contribution

It demonstrates that in two dimensions, disorder completely suppresses the Mott gap even at strong interactions, resulting in a universal glassy state with specific scaling properties.

Findings

Disorder destroys the Mott gap in 2D fermionic systems.

The probability of a nonzero gap follows a universal curve.

A scaling function for the susceptibility of the glassy state is provided.

Abstract

We study the competition between interactions and disorder in two dimensions. Whereas a noninteracting system is always Anderson localized by disorder in two dimensions, a pure system can develop a Mott gap for sufficiently strong interactions. Within a simple model, with short-ranged repulsive interactions, we show that, even in the limit of strong interaction, the Mott gap is completely washed out by disorder for an infinite system for dimensions $D\le 2$. The probability of a nonzero gap falls onto a universal curve, leading to a glassy state for which we provide a scaling function for the frequency dependent susceptibility.