Surface plasmon polaritons in a waveguide composed of Weyl and Dirac semimetals

Abstract

We investigate features of the surface plasmon polaritons (SPPs) hosted by a slot waveguide comprised of a Weyl semimetal in Voigt/Faraday configuration and a Dirac semimetal connected via a dielectric layer. In the Voigt configuration, SPP dispersion is nonreciprocal possessing unidirectional SPP modes in a wide range of frequency. However, the reciprocal SPP dispersion of the Faraday configuration composes of two distinct dispersion bands existing below or above the bulk plasmon frequency depending on the selection of the materials realizing Weyl and Dirac semimetal phases. We explain that these SPP modes are tunable with the thickness of the dielectric layer, the chemical potentials of the semimetals and the separation of the Weyl nodes in the Weyl semimetal. These structures provide a high level of functionality and tunability and may be employed in optical devices based on the unidirectional SPPs. • The slot waveguide allows unidirectional propagation of surface plasmon polaritons. • Surface plasmon polariton modes show new features in the Faraday configuration. • Thickness of the dielectric layer can be used to control surface plasmon polariton modes. • Chiral anomaly effect of the Weyl semimetal can be utilized to control the surface plasmon polariton modes.