Transport properties of high-quality ultrathin two-dimensional superconducting Mo₂C crystals and heterostructures

There is particularly interesting in the studies on highly crystalline 2D superconductors. Recently, we have obtained high-quality ultrathin Mo₂C crystals and graphene/Mo₂C heterostructures by means of chemical vapor deposition method. Here, we report on transport measurements on superconducting Mo₂C crystals and heterostructures in the 2D limit. We observe magnetoresistance (MR) oscillations and negative MR at low magnetic fields for temperature far below superconducting transition temperature. We discuss that these anomalous behaviors can be understood quantitatively by including the effects of inhomogeneous superconducting phase and quantum fluctuations. For graphene/ Mo₂C heterostructures, we demonstrate the realization of highly transparent Josephson junction devices based on these strongly coupled heterostructures.