Magnetization signatures of light-induced quantum Hall edge states

TL;DR

This paper proposes a method to detect light-induced quantum Hall edge states in topological materials through their magnetic signatures, offering a robust way to observe Floquet topological phases experimentally.

Contribution

It introduces a protocol to measure the magnetization of Floquet topological phases, overcoming common experimental challenges and enabling selective occupation of edge states.

Findings

Magnetization shows a universal linear dependence on chemical potential.

The proposed detection method is feasible with current experimental techniques.

Edge states can be selectively occupied and measured via magnetic signatures.

Abstract

Circularly polarised light opens a gap in the Dirac spectrum of graphene and topological insulator (TI) surfaces, thereby inducing a quantum Hall-like phase. We propose to detect the accompanying edge states and their current by the magnetic field they produce. The topological nature of the edge states is reflected in the mean orbital magnetization of the sample, which shows a universal linear dependence as a function of a generalized chemical potential - independent of the driving details and the properties of the material. The proposed protocol overcomes several typically encountered problems in the realization and measurement of Floquet phases, including the destructive effects of phonons and coupled electron baths and provides a way to occupy the induced edge states selectively. We estimate practical experimental parameters and conclude that the magnetization signature of the Floquet topological phase may be detectable with current techniques.