Scattered field from a dielectric-topological insulator rough interface using perturbation theory

Abstract

Scattering from a dielectric-topological insulator (TI) rough interface is studied using perturbation theory (PT). Two models characterized by magneto-electric pseudo scalar ψ and surface admittance γ for TI material are incorporated in the analysis. The zeroth order solution describes the reflection and transmission properties of the flat TI interface. Results are reported for various values of ψ and γ. The Brewster angle is shifted while it occurs at 58°for the dielectric case. The cross polarized reflection coefficients become small as the value of γ is increased. The first order scattering coefficients represent the contribution by superimposed roughness on the flat interface. Numerical results show that for γ-model, the first order co-polarized scattered field increases as γ is increased while the cross polarized field decreases. It is noted that the model defined by γ can better describe the scattering properties of the TI rough interface both theoretically and practically.