INTERFERENCE OF 2 ELECTRONS ENTERING A SUPERCONDUCTOR

The subgap conductivity of a normal-superconductor (NS) tunnel junctio n is thought to be due to tunneling of two electrons. There is a stron g interference between these two electrons, originating from the spati al phase coherence in the normal metal at a mesoscopic length scale an d the intrinsic coherence of the superconductor. We evaluated the inte rference effect on the transport through an NS tunnel junction. We pro pose the layouts to observe drastic Aharonov-Bohm and Josephson effect s.