Interaction-enhanced integer quantum Hall effect in disordered systems

TL;DR

This paper investigates how interactions and disorder influence the quantum Hall effect in two-dimensional systems, revealing that interactions can both induce and stabilize topological phases even amid disorder.

Contribution

It introduces a dynamical mean-field theory approach to analyze topological invariants and demonstrates how interactions modify the phase diagram in disordered quantum Hall systems.

Findings

Interactions can induce the integer quantum Hall effect in trivial insulators.

In topologically non-trivial regimes, interactions hinder Anderson localization.

Interactions broaden the topological phase regime in disordered systems.

Abstract

We study transport properties and topological phase transition in two-dimensional interacting disordered systems. Within dynamical mean-field theory, we derive the Hall conductance, which is quantized and serves as a topological invariant for insulators, even when the energy gap is closed by localized states. In the spinful Harper-Hofstadter-Hatsugai model, in the trivial insulator regime, we find that the repulsive on-site interaction can assist weak disorder to induce the integer quantum Hall effect, while in the topologically non-trivial regime, it impedes Anderson localization. Generally, the interaction broadens the regime of the topological phase in the disordered system.