Evidence of two-electron tunneling interference in Nb/InAs junctions
  The impact of junction transparency in driving phase-coherent charge transfer across diffusive semiconductor-superconductor junctions is demonstrated. We present conductivity data for a set of Nb-InAs junctions differing only in interface transparency. Our experimental findings are analyzed within the quasi-classical Green-function approach and unambiguously show the physical processes giving rise to the observed excess zero-bias conductivity. 
Antonio Badolato, Francesco Giazotto, Marco Lazzarino, Pasqualantonio   Pingue, Fabio Beltram, Carlo Lucheroni, Rosario Fazio