Photo-induced Chern Insulating States in Semi-Dirac Systems

Abstract

Two-dimensional semi-Dirac materials have quadratic dispersion relation along one direction and linear dispersion relation, similar to low energy graphene dispersion, along the other orthogonal direction. We study the topological phase transition in such two dimensional systems. The semi- Dirac Hamiltonian has two gapless Dirac nodes in the presence of timereversal symmetry and mirror symmetry. We show that by impinging light on the surface of a semi-Dirac material, gap opens because of time-reversal symmetry breaking and turning the system into a Chern insulator. Firstly, we show that the intensity of circularly polarized light can be used as a knob to induce topological states with non-zero Chern number in gapless semi-Dirac system. Secondly, for a gapped semi-Dirac system, by fixing the intensity and a frequency of the incident light, we induce topological transition as a function of polarization of the incident light.