Floquet High Chern Insulators in Periodically Driven Chirally Stacked Multilayer Graphene

TL;DR

This paper predicts that periodically driven chirally stacked multilayer graphene can be turned into high Chern number Floquet topological insulators with tunable properties using circularly polarized light and voltage gating.

Contribution

It introduces a method to induce and control high Chern number Floquet topological phases in multilayer graphene via light and gating.

Findings

Floquet Chern insulators with tunable high Chern number $\pm N$

Topological phase transition between FCI and valley Hall insulator

Unidirectional valley-polarized edge states at domain walls

Abstract

Chirally stacked $N$-layer graphene is a semimetal with $\pm p^N$ band-touching at two nonequivalent corners in its Brillioun zone. We predict that an off-resonant circularly polarized light (CPL) drives chirally stacked $N$-layer graphene into a Floquet Chern Insulators (FCIs), a.k.a. quantum anomalous Hall insulators, with tunable high Chern number $C_F=\pm N$ and large gaps. A topological phase transition between such a FCI and a valley Hall (VH) insulator with high valley Chern number $C_v=\pm N$ induced by a voltage gate can be engineered by the parameters of the CPL and voltage gate. We propose a topological domain wall between the FCI and VH phases, along which perfectly valley-polarized $N$-channel edge states propagate unidirectionally without backscattering.