Observation of superconductivity induced by a point contact on 3D Dirac semimetal Cd3As2 crystals

Point contact spectroscopy measurements show a superconducting phase around the point contact region on the surface of the 3D Dirac semimetal Cd 3 As 2 . Three-dimensional (3D) Dirac semimetals, which possess 3D linear dispersion in the electronic structure as a bulk analogue of graphene, have lately generated widespread interest in both materials science and condensed matter physics 1 , 2 . Recently, crystalline Cd 3 As 2 has been proposed and proved to be a 3D Dirac semimetal that can survive in the atmosphere 3 , 4 , 5 , 6 , 7 , 8 , 9 . Here, by using point contact spectroscopy measurements, we observe exotic superconductivity around the point contact region on the surface of Cd 3 As 2 crystals. The zero-bias conductance peak (ZBCP) and double conductance peaks (DCPs) symmetric around zero bias suggest p -wave-like unconventional superconductivity. Considering the topological properties of 3D Dirac semimetals, our findings may indicate that Cd 3 As 2 crystals under certain conditions could be topological superconductors 10 , 11 , 12 , 13 , which are predicted to support Majorana zero modes or gapless Majorana edge/surface modes in the boundary depending on the dimensionality of the material 14 , 15 , 16 , 17 .