Multiterminal Conductance of a Floquet Topological Insulator

TL;DR

This paper uses Floquet scattering theory to simulate the conductance and quantum Hall response of a Floquet topological insulator, revealing that edge states influence Hall plateaus independently of topological invariants.

Contribution

It demonstrates that the dc quantum Hall conductance in Floquet topological insulators depends on edge states contributing to the density of states, not solely on topological invariants.

Findings

Laser-induced edge states lead to quantum Hall plateaus.

Hall plateau magnitude is determined by edge states contributing to the density of states.

Hall conductance is not directly linked to topological invariants.

Abstract

We report on simulations of the dc conductance and quantum Hall response of a Floquet topological insulator using Floquet scattering theory. Our results reveal that laser-induced edge states in graphene lead to quantum Hall plateaus once imperfect matching with the non-illuminated leads is lessened. But the magnitude of the Hall plateaus is not directly related to the number and chirality of all the edge states at a given energy as usual. Instead, the plateaus are dominated only by those edge states adding to the dc density of states. Therefore, the dc quantum Hall conductance of a Floquet topological insulator is not directly linked to topological invariants of the full the Floquet bands.