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.