Reentrance of conductance in mesoscopic normal-metal/superconductor junctions

Abstract

Two different kinds of mesoscopic N-S-N junctions were fabricated by sandwiching Al or Pb film between two closely separated Au wires. dV/dI versus V curves for an Au-Pb-Au junction show a sharp zero-bias dip, while those for an Au-Al-Au show a reentrant zero-bias maximum. Interference between conjugate electrons and holes at an interface with different degree of transparency is responsible for the contrasting behavior. (C) 2000 Elsevier Science B.V. All rights reserved.