Klein tunneling of Weyl magnons

TL;DR

This paper explores the Klein tunneling phenomenon of Weyl magnons in magnetic materials, analyzing how different types of Weyl magnons transmit through potential barriers and how their bosonic nature affects current behavior.

Contribution

It introduces the study of Klein tunneling in Weyl magnons, highlighting the effects of cone tilting and double Weyl structures on magnon transmission and current characteristics.

Findings

Tilted Weyl cones reduce magnetization current during tunneling.

Double Weyl magnons show no Klein tunneling in quadratic dispersion directions.

Magnon current-voltage behavior differs from electrons due to bosonic statistics.

Abstract

Similar to Weyl semimetals, in magnetic materials, magnon bands can host Weyl points, around which the bosonic excitations are called Weyl magnons. Here, we investigate the Klein tunneling of Weyl magnons, during the process of which Weyl magnons tunnel through a high potential barrier. Specifically, we study the magnetization current carried by Weyl magnons in a quasi-one-dimensional magnetic wire, in the middle of which a gate magnetic field is applied to generate a potential barrier. The transmission probability is calculated and the Landauer-B\"uttiker formalism is used to find the magnetization current. Various types of Weyl magnons are considered, including isotropic, tilted, and double Weyl magnons. Unlike in Weyl semimetals where fermionic statistics is in charge and the current oscillates with the gate field as a result of Fabry-P\'erot resonances, here Bose distribution smears out the oscillations. We find that the tilting of the Weyl cone causes the decrease of the magnetization current from Klein tunneling, while for double Weyl magnons, Klein tunneling is absent in the direction of quadratic dispersion, but is enhanced in the direction of linear dispersion. Our results show that the behaviour of the current-voltage characteristics of magnons is rather different from that of electrons due to different statistics, although the single-particle properties, such as the transmission probabilities, are the same for both Weyl bosons and Weyl fermions.