Influence of an electric field on the optical properties of few-layer graphene with AB stacking

The effect of perpendicular electric field (F) on optical properties of the AB-stacked few-layer graphene, made up of two, three, or four graphite sheets, is explored through the gradient approximation. In contrast to the featureless optical spectra of graphene, the low-energy absorption spectra of few-layer graphene with AB stacking exhibit many jumping structures, which result from the band-edge states caused by the stacking effect, in the absence of an electric field. Remarkably, F causes the subband (anti)crossing, changes the subband spacing, produces the oscillating bands, and increases the band-edge states. It, therefore, follows that the field-modulating spectra with sharp peaks are generated. Moreover, the frequency of peak, which is strongly dependent on the layer number and the field strength, is predicted. Above all, the predicted absorption spectra and the associated electronic properties could be verified by the optical measurements.