Zero-bias conductance peak and Josephson effect in graphene-NbTiN   junctions
  We report electronic transport measurements of graphene contacted by NbTiN electrodes, which at low temperature remain superconducting up to at least 11 Tesla. In devices with a single superconducting contact, we find a more than twofold enhancement of the conductance at zero bias, which we interpret in terms of reflectionless tunneling. In devices with two superconducting contacts, we observe the Josephson effect, bipolar supercurrents and Fraunhofer patterns. 
Mihai Popinciuc and Victor E. Calado and Xing L. Liu and Anton R.   Akhmerov and Teun M. Klapwijk and Lieven M. K. Vandersypen
cond-mat.mes-hall cond-mat.supr-con