Observation of an edge supercurrent in Weyl semimetal MoTe2

We report evidences and interpretations for a robust edge supercurrent in type II Weyl semimetal MoTe2 in the superconducting regime, where T < Tc = 100 mK at ambient pressure. We fabricated MoTe2 devices (60 – 120 nm thickness) with Au contacts through mechanical exfoliation and nanofabrication. Transport measurements of differential resistance dV/dI versus applied bias and magnetic field B shows a periodic oscillation of critical current Ic with a scalloped profile. The oscillation mode remains coherent and the associated area to its frequency saturates to the physical area of sample with an increasing magnetic field. These observations demonstrate a superconducting edge mode with the width less than 10 nm. We describe the edge condensate with a Ginzburg Landau wave function that is independent from the bulk condensate. Fluxoid quantization causes the edge superfluid velocity to vary, resulting in the scalloped profile. Weak excitations trailing from the scalloped boundaries in Ic vs. B plots exhibit unusual asymmetries.