Buckled graphene-like materials in ultrashort and strong optical fields

This paper investigates the interaction of buckled Dirac materials (silicene and germanene) with ultrashort and ultrastrong optical pulses. Highly intensive few-cycle pulses strongly modify the electronic and optical properties of these two-dimensional materials. Electron dynamics in such a short optical pulse is coherent and can be robustly controlled by altering the propagation direction, as well as the polarization angle of the pulse. The strong nonlinearity of the system for fields applied ( V/${\AA}$ ) causes the violation of the charge (C) and parity (P) symmetries, effectively reducing the system's symmetry from hexagonal to triangular. Such symmetry violations are related to the electron transfer between the sublattices caused by the normal field component and result in nonreciprocity, optical rectification and the appearance of a cross current.