Dynamic conductivity of ac–dc-driven graphene superlattice

•Dynamical conductivity of ac–dc driven graphene superlattice was calculated.•Conductivity dependence on the ac electric field frequency was studied.•Numbers of frequency diapasons corresponding to negative conductivity were found.•Region of negative conductivity can be expanded by transversal dc field changing.

The dynamic conductivity of graphene superlattice in the presence of ac electric field and dc electric field with longitudinal and transversal components with respect to superlattice axis was calculated. In the case of strong transversal component of dc field conductivity of graphene superlattice was shown to be such as if the electrons had got the effective mass. In the case of weak transversal component of dc field conductivity was shown to change its sign if the frequency of ac field was an integer multiple of half of Bloch frequency.