Floquet Weyl fermions in three-dimensional stacked graphene systems irradiated by circularly polarized light

Abstract

Using Floquet theory, we illustrate that Floquet Weyl fermions can be created in three-dimensional stacked graphene systems irradiated by circularly polarized light. One or two semi-Dirac points can be formed due to overlapping of Floquet subbands. Each pair of Weyl points have a two-component semi-Dirac point parent, instead of a four-component Dirac point parent. Decreasing the light frequency will make the Weyl points move in the momentum space, and the Weyl points can approach to the Dirac points when the frequency becomes very small. The frequency-amplitude phase diagram is worked out. It is shown that there exist Fermi arcs in the surface Brillouin zones in semi-infinitely stacked and finitely multilayered graphene systems irradiated by circularly polarized light. The Floquet Weyl points emerging due to the overlap of Floquet subbands provide a new platform to study Weyl fermions.