Angular-momentum-selective nanofocusing with Weyl semimetals

TL;DR

This paper presents a theoretical study showing that magnetic Weyl semimetals can focus surface plasmon polaritons with specific orbital angular momentum at a tip's end, enhancing nanofocusing capabilities.

Contribution

It introduces a novel theoretical framework for orbital angular momentum selective nanofocusing using Weyl semimetals, contrasting with traditional metals.

Findings

Surface plasmon polaritons are modified by the axion term in Weyl semimetals.

All modes with a given sign of orbital angular momentum can be focused at the tip end.

This expands the potential for technologies utilizing orbital angular momentum.

Abstract

We investigate the theory of surface plasmon polaritons on a magnetic Weyl semimetal conical tip. We show that the axion term in the effective electrodynamics modifies the surface plasmon polariton dispersion relation and allows all modes with a given sign of the orbital angular momentum to be focused at the end of the tip. This is in contrast with normal metals, in which only one mode can reach the end. We discuss how this orbital angular momentum nanofocusing expands the potential of technologies that use this degree of freedom.