Dynamical delocalization in disordered 2D Chern insulators

TL;DR

This paper demonstrates the existence of dynamical delocalization energies in disordered 2D Chern insulators, revealing a disorder-driven transition that extends the understanding of topological phases under randomness.

Contribution

It introduces a novel approach to prove dynamical delocalization in the disorder parameter, not just energy, in 2D Chern insulators with disorder.

Findings

Robustness of the topological index despite disorder

Existence of dynamical delocalization energies in the model

Proof of Anderson transition even with closing spectral gaps

Abstract

We show the existence of energies exhibiting dynamical delocalization in discrete 2D Chern insulators perturbed by a random potential in a general setting. Our proof exploits two main features of the model: jumps in the integer value of the Chern character and continuity of averaged spectral projections in both energy and disorder parameters. This allows us to show robustness of the topological index in the presence of disorder, which, combined with existing methods to prove dynamical localization, allows us to provide detailed information on the phase diagram of the model. The novelty of our approach is that we are able to show dynamical delocalization in the disorder parameter, and not only in the energy parameter, which allows to prove Anderson metal-insulator transition even when spectral gaps close due to the strength of disorder.