# Disorder induced transitions in resonantly driven Floquet Topological Insulators

## TL;DR

This paper studies how disorder affects Floquet topological insulators in quantum wells, showing that disorder can both destroy and induce topological phases, leading to a Floquet Topological Anderson Insulator.

## Contribution

It demonstrates that disorder can induce a topological phase transition in Floquet insulators, revealing conditions for realizing a Floquet Topological Anderson Insulator.

## Key findings

- Topological phase persists with disorder if a mobility gap exists.
- Strong disorder can localize states and transition the system to a trivial insulator.
- Disorder can induce a transition from trivial to topological phases, creating a Floquet Topological Anderson Insulator.

## Abstract

We investigate the effects of disorder in Floquet topological insulators (FTIs) occurring in semiconductor quantum wells. Such FTIs are induced by resonantly driving a transition between the valence and conduction band. We show that when disorder is added, the topological nature of such FTIs persists as long as there is a mobility gap at the resonant quasi-energy. For strong enough disorder, this gap closes and all the states become localized as the system undergoes a transition to a trivial insulator. Interestingly, the effects of disorder are not necessarily adverse: we show that in the same quantum well, disorder can also induce a transition from a trivial to a topological system, thereby establishing a Floquet Topological Anderson Insulator (FTAI). We identify the conditions on the driving field necessary for observing such a transition.