Nonreciprocal plasmonic waveguide from Weyl semimetals

Weyl semimetals are intensely investigated topological materials, in which valence and conduction bands touch in a finite number of points. They possess nontrivial transport properties, which can be traced back to the presence of an axionic term in the emergent electrodynamics. In this talk, I will address a cylindrical plasmonic waveguide consisting of a magnetic Weyl semimetal embedded in a dielectric medium. I will present the main features of the dispersion relation of surface plasmons and show its dependence on the cylinder radius and the position of the band-touching points. In contrast to metallic waveguides, the axionic term determines an asymmetry of the surface plasmon dispersion and a giant splitting of the plasmon velocity in bands of opposite orbital angular momentum, with potential technological applications.

Reference: M. Peluso, A. De Martino, R. Egger, and F. Buccheri, "Nonreciprocal Weyl semimetal waveguide", arXiv:2410.01503 (2024).