Mesoscopic proximity effect in double-barrier superconductorormal-metal junctions - art. no. 100508

摘要

We report transport measurements down to T=60 mK of SININ and SNIN structures in the diffusive limit. We fabricated Al-AlOx/Cu/AlOx/Cu (SININ) and Al/Cu/AlOx/Cu (SNIN) vertical junctions. A zero-bias anomaly was observed in a metallic SININ structure. We attribute this peak of conductance to coherent multireflections of electrons between the two tunnel barriers. This conductance maximum is quantitatively fit by the relevant theory of mesoscopic SININ structures. When the barrier at the SN interface is removed (SNIN structure), we observe a peak of conductance at finite voltage accompanied by an excess of subgap conductance. [References: 30]