Quantized large-bias current in the anomalous Floquet-Anderson insulator

TL;DR

This paper investigates the transport properties of the anomalous Floquet-Anderson insulator, revealing that a large bias induces quantized charge transport through topologically protected edge modes in a disordered, driven 2D system.

Contribution

It demonstrates that the AFAI phase exhibits quantized charge transport at large bias, highlighting its unique far-from-equilibrium transport signatures due to topological edge states.

Findings

Quantized charge transport occurs at large bias in AFAI.

Edge modes become fully occupied, leading to quantized current.

Transport signatures are robust despite bulk localization.

Abstract

We study two-terminal transport through two-dimensional periodically driven systems in which all bulk Floquet eigenstates are localized by disorder. We focus on the Anomalous Floquet-Anderson Insulator (AFAI) phase, a topologically-nontrivial phase within this class, which hosts topologically protected chiral edge modes coexisting with its fully localized bulk. We show that the unique properties of the AFAI yield remarkable far-from-equilibrium transport signatures: for a large bias between leads, a quantized amount of charge is transported through the system each driving period. Upon increasing the bias, the chiral Floquet edge mode connecting source to drain becomes fully occupied and the current rapidly approaches its quantized value.