Light-induced Topological Insulator with Superlattice Structure

We study the superlattice structure created by light on 2D material. Specifically, we investigate the monolayer graphene irradiated by circularly-polarized (CP) beam where the beam amplitude has spatial periodicity. We numerically study the phase transition between the topological insulator and the normal insulator depending on the superlattice size. To examine the role of lattice shape in the topological property of the system, we investigate the topological phase transition happening in the sheared lattice. By superposing different kinds of beams, our scheme can create a more complicated lattice such as kagome lattice. This wide tunability of lattice can be used for further investigation of interesting dynamics of electrons.