Floquet Engineered Vortex States in Dirac-like Systems

Periodic driving of Dirac-like materials via irradiation leads to the photon-dressing of their electronic bands and a concomitant topological phase change. Light offers multiple degrees of freedom that impact its interaction with matter. Conventionally, variations in light’s intensity, frequency, and polarization have been used to optically tune various phases of matter. However, additional degrees of tunability can arise from the spatial control of optical beams. Vortex-light beams are examples of such sources of radiation as these beams carry orbital angular momentum in addition to their polarization. This work considers a two-dimensional massive Dirac-like system subjected to a monochromatic vortex light beam. Using Floquet’s theorem, we identify the set of frequencies and polarizations for which angular momentum is conserved and find the eigenstates of the space-dependent Floquet Hamiltonian. We present a full description of the photo-induced vortex states that emerge in the irradiated system in terms of their real space extension, vorticity, and topological properties.