In this paper we report about the transport properties of mesoscopic normal-metal/superconductor (NS) hybrid systems with two different junction layouts. One is a junction fabricated by overlaying S on N wire and the other with S sandwiched between two N wires, forming an NSN structure. At zero bias all the junctions exhibited a sharp decrease of dV/dI, which is believed to arise from the interference between the disorder-scattered and the Andreev-reflected quasiparticles. A small magnetic field corresponding to one flux quantum through the normal metal region, applied in parallel with the NS junction, easily suppressed the anomalous zero-bias conductance enhancement for the sandwich-junction sample. This high sensitivity to a small magnetic field observed in our systems of mesoscopic NS junctions in a diffusive-transport regime directly confirms the electron-hole-interference origin of the zero-bias anomaly.
Bibliographical noteFunding Information:
We wish to acknowledge the useful discussions with Dr. Hekking and Prof. Lambert. One of us (N.K.) appreciates the useful discussions with Dr. Galaktionov, Mr. Cho, and Prof. Ryu. This work was supported by KOSEF, BSRI, MARC, and POSTECH.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry