3D Topological Plasmons in Weyl Semimetals

TL;DR

This paper explores the topological properties of bulk, surface, and edge plasmons in Weyl semimetals under magnetic fields, revealing novel unidirectional and Fermi-arc plasmons with potential applications in topological plasmonics.

Contribution

It introduces the concept of topologically protected Weyl plasmons, including unidirectional and Fermi-arc plasmons, and demonstrates their controllability and unique dispersion properties.

Findings

Existence of unidirectional surface plasmons consistent with bulk topology

Fermi-arc plasmons form a new class of 3D topological plasmons

A gapless unidirectional edge plasmon protected by topology

Abstract

We systematically investigate the properties of bulk, surface and edge plasmons in Weyl semimetals in presence of a magnetic field. It is found that unidirectional plasmons with different properties exist on different surfaces, which is in consistent with the nontrivial topology of the three-dimensional (3D) bulk plasmons. These novel plasmons possess momentum-location lock and may travel between surfaces. The anomalous Hall conductivity brings about abundant anisotropic plasmon dispersions, from linear to parabolic or even hyperbolic bands. With the help of a semiclassical picture for the formation of the Weyl orbits, we point out the Fermi-arc plasmons at opposite surfaces can make up another unique 3D topological plasmon. Furthermore, there is a gapless unidirectional edge plasmon protected by the topology whose direction and position can be controlled by external field. Our work thus uncovers topological features of Weyl plasmons, which may have important applications in photoelectric devices based on chiral/topological plasmonics.