Interaction of Phosphorene with Ultrafast Optical Pulse

We study theoretically interaction of monolayer black phosphorous, phosphorene, with an ultrafast optical pulse with the duration of a few femtoseconds. For such short pulse the electron dynamics is coherent and can be described by the time-dependent Schrodinger equation. A conduction band population in the reciprocal space shows hot spots near the point, at which the interband dipole coupling is the largest. We show that the interband electron dynamics is irreversible, i.e., the residual conduction band population is comparable to the maximum conduction band population during the pulse. Also, the electron redistribution between the bands generates an electric current and finally causes a charge transfer through the phosphorene during the pulse. The direction of the charge transfer is the same as the direction of the field maximum.