Weyl fermions induced Magnon electrodynamics in Weyl semimetal

TL;DR

This paper explores how Weyl fermions in Weyl semimetals induce a topological electromagnetic response that affects magnetic fluctuations, leading to novel magnon and polariton phenomena.

Contribution

It demonstrates the impact of Weyl fermion-induced anomalies on magnon dynamics and electromagnetic responses in Weyl semimetals, revealing new physical behaviors.

Findings

Electric field-assisted magnetization dynamics

Additional gapless magnon dispersion

Polariton bands with sibling features in magnetic fields

Abstract

Weyl fermions, which are fermions with definite chiralities, can give rise to anomalous breaking of the symmetry of the physical system which they are a part of. In their (3+1)-dimensional realizations in condensed matter systems, i.e., the so-called Weyl semimetals, this anomaly gives rise to topological electromagnetic response of magnetic fluctuations, which takes the form of non-local interaction between magnetic fluctuations and electromagnetic fields. We study the physical consequences of this non-local interaction, including electric field assisted magnetization dynamics, an extra gapless magnon dispersion, and polariton behaviors that feature "sibling" bands in small magnetic fields.