Josephson junctions of Weyl semimetal WTe2 induced by spontaneous nucleation of PdTe superconductor

Abstract We report on the fabrication of Josephson junction devices with weak links utilizing the Weyl and higher-order topological semimetal WTe 2 . We show that the WTe 2 /Pd contact annealed at a low temperature of 80 °C did not exhibit superconducting properties because neither WTe 2 nor Pd are superconductors in the ground state. Upon 180 °C annealing, spontaneous formation of superconducting PdTe due to Pd diffusion enabled us to obtain the interface between WTe 2 and superconductor suitable for the Josephson junction. This result is a facile technique to make a Josephson junction and induce Cooper pairs into topological telluride semimetals.