Simulation of terahertz plasmons in graphene with grating-gate structures

Frequency dispersion and damping mechanisms of two-dimensional plasmons in graphene in the terahert (THz) range are studied by a numerical simulation based on the Boltzmann equation. The fundamental plasmon mode in a singlegrating-gate structure is studied, and the coupling effect of plasmons in the gated and ungated regions are revealed. It is shown that the plasmon frequency as well as its gate-voltage tunability depend strongly on the coupling. It is also demonstrated that damping rates due to the acoustic-phonon scattering at room temperature and short- and finite-range disorder scattering can be on the order of 10¹¹ s^-1, depending on the level of disorders.