Photogalvanic Effect in Nitrogen-Doped Monolayer MoS2 from First Principles

We investigate the photogalvanic effect in nitrogen-doped monolayer molybdenum disulfide (MoS2) under the perpendicular irradiation, using first-principles calculations combined with non-equilibrium Green function formalism. We provide a detailed analysis on the behavior of photoresponse based on the band structure and in particular the joint density of states. We thereby identify different mechanisms leading to the existence of zero points, where the photocurrent vanishes. In particular, while the zero point in the linear photovoltaic effect is due to forbidden transition, their appearance in the circular photovoltaic effect results from the identical intensity splitting of the valance band and the conduction band in the presence of Rashba and Dresslhaus spin-orbit coupling. Furthermore, our results reveal a strong circular photogalvanic effect of nitrogen-doped monolayer MoS2, which is two orders of magnitude larger than that induced by the linearly polarized light.