Temperature-Dependent Electromagnetic Surface Wave Supported by Graphene-Loaded Indium Antimonide Planar Structure

Abstract

In this study, the propagation characteristics of EM surface waves supported by the graphene-coated indium antimonide (InSb) planar waveguide have been investigated theoretically and numerically. The modeling of graphene has been performed by use of Kubo formalism whereas the relative permittivity of indium antimonide has been calculated using Drude’s model. The results for transverse electric (TE) and transverse magnetic (TM) polarized surface waves have been computed analytically and numerically. The major challenge is to model the atomically thick graphene sheet over the InSb grounded slab. To get the temperature-dependent characteristic equation for the electromagnetic surface waves, the surface current boundary conditions’ approach has been employed. The numerical results have been computed for both the TE and TM polarization states and reported that the TE does not support the propagation of surface waves. The dispersion relation, effective mode index, phase speed, propagation length, and field profile have been computed in Mathematica under TM polarization. The graphene and indium antimonide have been found active for low and high Terahertz regions, respectively. As temperature increases, the plasma frequency of the InSb increases due to this reason with the increase of temperature and the resonance frequency, leading to a shift in the dispersion curve. Moreover, with the increase of temperature, the effective wave number of transverse magnetic polarized surface waves also increases. Resultantly, the confinement of such surface waves supported by graphene-loaded InSb increases. It is shown that with the variation of temperature of indium antimonide, the surface waves propagating across the interface can be tuned in the Terahertz region and can be exploited for thermo-optical sensing, near-field communications waveguides, and graphene-based temperature sensor designing.