Abstract
Plasma waves in graphene-based heterostructures with massless (neutrino-like) two-dimensional electron gas and with a highly conducting substrate (n+-Si) serving as a gate and an isolating gate layer (SiO2) are studied. Using the developed model, we show that the sufficiently long plasma waves exhibit a linear (sound-like) dispersion with the wave velocity determined by the gate layer thickness and the gate voltage. The plasma wave velocity in graphene heterostructures can significantly exceed the plasma wave velocity in the commonly employed semiconductor gated heterostructures. The gated graphene heterostructures can be used in different novel voltage tunable THz devices which utilize the plasma waves.