Comparison of the terahertz and optical characteristics of graphene and silicene nanoribbons utilizing first-principles approach

Optical applications of graphene and related two-dimensional materials are continuously taking interest. In this study, accurate first-principles simulations are utilized for obtaining the terahertz and optical characteristics of realistic graphene and silicene nanoribbons (GNRs and SiNRs). Density functional theory is used for calculating the electron density and then Kubo-Greenwood formalism is applied for the computation and comparison of the complex dielectric functions of equivalent GNR and SiNR samples, which are found to be consistent with the previous results in the literature. Frequency-dependent complex conductivities of the devices under consideration are also obtained. The surface plasmon polariton (SPP) wave propagation properties of GNR and SiNR samples are then interpreted and compared. The frequency-dependent conductivity data are also imported into a full-wave electromagnetic simulation tool and the characteristics of the GNR and SiNR samples are evaluated for use as nanostrip transmission lines. It is found out that GNRs seem to be more advantageous compared to equivalent SiNRs from both SPP wave transmission frequency range and higher conductivity viewpoints.