Transition from Integer Quantum Hall State to Insulator

TL;DR

This paper investigates the disorder-induced transition from quantum Hall states to insulators in a lattice model, revealing direct transitions and topological insights that differ from earlier continuous model predictions.

Contribution

It demonstrates that extended states' positions remain fixed with increasing disorder, enabling direct transitions from quantum Hall to insulator states, supported by a topological analysis.

Findings

Extended states' positions do not shift with disorder.

Direct transitions from quantum Hall states to insulators occur.

Topological properties explain the transition mechanism.

Abstract

We study disorder induced transition between quantum Hall states and insulator state in a {\it lattice} model. We find the positions of the extended states do not change as disorder strength is varied. As a consequence, there are direct transitions from all Landau level quantum Hall states to insulator states, in contrast to the global phase diagram from early studies based on continuous models. We also provide the microscopic understanding of the transition in terms of the topological properties of the system.