Tuning of Bilayer Graphene Heterostructure by Horizontally Incident Circular Polarized Light

TL;DR

This paper theoretically explores how horizontally incident circular polarized light can tune the electronic and topological properties of bilayer graphene heterostructures, predicting control over band gaps and quantum anomalous Hall phases.

Contribution

It introduces a model for controlling bilayer graphene's properties using circular polarized light, including tuning band gaps and inducing topological phases.

Findings

Amplitude of light can tune the band gap and topological properties.

Predicted spin-polarized quantum anomalous Hall phase with Chern number one.

Incident angle affects edge state dispersion in nanoribbons.

Abstract

We theoretically investigated the Floquet states of bilayer graphene heterostructure under the irradiation by horizontally incident circular polarized light. The in-plane and out-of-plane electric field of the light periodically perturbs the intra-layer and inter-layer hopping, respectively. For circular polarized light, the two components of the electric field has $\pi/2$ phase difference, so that the two types of hopping are periodically perturbed with the $\pi/2$ phase difference, which modify the effective inter-layer hopping. We focus on the model of bilayer graphene in the heterostructure of antiferromagnetic van der Walls spin valve. The amplitude of the irradiation can tune the band gap and topological properties of the bulk state. The spin-polarized quantum anomalous Hall phase with Chern number being one is predicted. The incident angle of the irradiation can tune the band gap and dispersion of the edge states in zigzag nanoribbons.