Terahertz conductivity of monolayer MoS _2

We calculate the electrical conductivity of suspended and supported monolayer MoS _2 at terahertz (THz) frequencies by means of EMC–FDTD, a multiphysics simulation tool combining an ensemble Monte Carlo (EMC) solver for electron transport and a finite-difference time-domain (FDTD) solver for full-wave electrodynamics. We investigate the role of carrier and impurity densities, as well as substrate choice (SiO _2 or hexagonal boron nitride, hBN), in frequency-dependent electronic transport. Owing to the dominance of surface-optical-phonon scattering, MoS _2 on SiO _2 has the lowest static conductivity, but also the weakest overall frequency dependence of the conductivity. In fact, at high THz frequencies, the conductivity of MoS _2 on SiO _2 exceeds that of either suspended or hBN-supported MoS _2 . We extract the parameters for Drude-model fits to the conductivity versus frequency curves obtained from microscopic simulation, which may aid in the experimental efforts toward MoS _2 THz applications.