SINGLE-PARTICLE PROXIMITY EFFECT BETWEEN SUPERCONDUCTORS THROUGH A TUNNELING BARRIER

The single-particle proximity effect between superconductors separated by a tunneling barrier is observed experimentally in double tunneling junctions. The dependence of the single-particle proximity effect on a small voltage difference across the tunneling barrier is measured. An energy region Absolute value of E < DELTA appears to be typical for this effect because in this region the proximity-effect-induced superconducting density-of-states function is not smeared. It is possible to describe the single-particle proximity effect between superconductors within the extended McMillan tunneling model of the superconducting proximity effect.