Filamentary superconductivity in wrinkled PtSe2

Abstract

Platinum diselenide (PtSe2) is a recently discovered Dirac semi-metal, which is theoretically predicted to possess a superconducting transition at an extremely low temperature T c of 2 mK. However, it has not yet to be experimentally reported. We observe a filamentary superconducting transition at 2.3 K in the wrinkled PtSe2 induced by rapid thermal treatment. Certain crystalline deformation or phase transition occurs locally in PtSe2 due to the inhomogeneous strain induced during the temperature cycle, where T c could be significantly enhanced. The possibility of forming degraded PtSe2 or any superconducting compounds at the electric contacts during the thermal treatment is carefully ruled out. We investigate the magnetic field dependence of the superconductivity transition, i.e. the upper critical fields, and find the superconductivity in accordance with the Bardeen–Cooper–Schrieffer theory.