Simulation of carrier dynamics in graphene on a substrate at terahertz and mid-infrared frequencies

We calculate the complex conductivity of graphene in the terahertz (THz) to mid-infrared (mid-IR) frequency range using a numerical simulation that couples the two-dimensional (2D) ensemble Monte Carlo technique (EMC) for carrier transport, the three-dimensional (3D) finite-difference time-domain (FDTD) technique for electrodynamics, and molecular dynamics (MD) for short range Coulomb interactions. We demonstrate the effect of the typically used silicon-dioxide substrate on the high-frequency carrier dynamics in graphene and show good agreement between recent experimental results and our numerical simulations.