Chiral nodes and oscillations in the Josephson current in Weyl semimetals

Abstract

The separation of the Weyl nodes in a broken time-reversal symmetric Weyl semimetal leads to helical quasiparticle excitations at the Weyl nodes which, when coupled with overall spin conservation, allows only internodal 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 k₀L, where L is the length of the Weyl semimetal and 2k₀ is the internodal 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.