Chiral nodes and oscillations in the Josephson current in Weyl semimetals

TL;DR

This paper predicts a unique oscillation in the Josephson current in Weyl semimetals caused by chiral nodes, which can serve as an experimental signature for their existence.

Contribution

It introduces a novel theoretical prediction of Josephson current oscillations due to chiral nodes in Weyl semimetals, linking topological features to measurable transport phenomena.

Findings

Oscillation in Josephson current as a function of $k_0L$

Robustness of the oscillation against experimental conditions

Potential for experimental detection of chiral nodes

Abstract

The separation of the Weyl nodes in a broken time-reversal symmetric Weyl semimetal leads to helical quasi-particle excitations at the Weyl nodes, which, when coupled with overall spin conservation allows only inter-nodal transport at the junction of the Weyl semimetal with a superconductor. This leads to an unusual periodic oscillation in the Josephson current as a function of $k_0L$, where $L$ is the length of the Weyl semimetal and $2k_0$ is the inter-nodal distance. This oscillation is robust and should be experimentally measurable, providing a direct path to confirming the existence of chiral nodes in the Weyl semimetal.