An excess low-voltage conductance is observed in Nb-InGaAs contacts at low temperatures and interpreted as being due to a pair current across the superconductor-semiconductor interface. This is the first observation of a pair current, a nonequilibrium manifestation of the proximity effect, in junctions having one electrode which is not a superconductor. A model is presented which accounts for the observed behavior. In addition to the pair current, it is demonstrated that these junctions exhibit excess conductance due to Andreev scattering.
ASJC Scopus subject areas
- Physics and Astronomy(all)