▎ 摘　　要

The tunneling processes between independently contacted graphene sheets separated by thin insulator are restricted by the momentum and energy conservation laws. Because of this, both dissipative tunneling transitions, with momentum transfer due to disorder scattering, and nondissipative regime of tunneling, which appears due to intersection of electron and hole branches of energy spectrum, must be taken into account. The tunneling current density is calculated for the graphene-boron nitride-graphene layers, which is described by the tight-binding approach, and for the predominant momentum scattering by static disorder. Dependencies of current on concentrations in top and bottom graphene layers, which are governed by the voltages applied through independent contacts and gates, are considered for the back- and double-gated structures. The current-voltage characteristics of the back- gated structure are in agreement with the recent experiment [Science 335, 947 (2012)]. For the double-gated structures, the resonant dissipative tunneling causes a 10-fold enhancement of response which is important for transistor applications. DOI: 10.1103/PhysRevB.87.075424