Conductance characteristics between a normal metal and a clean superconductor carrying a supercurrent

Abstract

The effect of a transverse supercurrent I-s up to the thermodynamic critical current on the low-temperature conductance characteristics between a normal metal N and a clean s- or d-wave superconductor (S) is theoretically investigated, covering from metallic contact (z=0) to the tunneling limit (zmuch greater than1). For d-wave S both (100) and (110) contacts are studied. Many features found are due to current-induced gap anisotropy and requires S to be in the clean limit. Near critical I-s and for zsimilar or equal to1, a three-humped structure appears for both s-wave S and d-wave S with (100) contact, signaling onset of current-induced gaplessness on the Fermi surface where gap originally exists.