Waveform control of currents in graphene by chirped few-cycle lasers

The residual current density in monolayer graphene driven by an intense few-cycle chirped laser pulse is investigated via numerical solution of the time-dependent Schrodinger equation in the strong field regime. Strikingly, it is found that by a purely chirped laser, a non-monotonic residual current is generated with increasing peak electric field strength.The basis of such a current control is a chirp- dependent Landau-Zener-Stuckelberg interference among different quantum pathways in the reciprocal space. Moreover, the directionality of residual currents can be controlled by chirp rate, following a simple sine-functional way. The control role of chirp rate is analogous to that of carrier-envelop-phase for a purely Fourier transform-limited pulse [Nature 550,224(2017)], but the control magnitude of the former is twice that the latter. This convenient chirp control of currents maybe useful for light-field-driven electronics in two-dimensional materials.