Pairing correlation effect on the resonant tunneling conductance through an ultrasmall superconducting grain

Abstract

We study superconducting pairing correlation (SPC) effect on low-temperature electron transport through a single electron transistor containing an ultrasmall superconducting grain with a gate electrode. It is shown that the SPC manifests itself in structures of zero-bias resonant conductance peaks, which appear successively with increase or decrease of the gate voltage. We focus our attention on the structures of the two adjacent resonant peaks which are equivalent each other if the SPC is completely negligible. It is shown that the two peak structures could differ from each other due to the SPC in actual experimental situations. This indicates that we can detect the SPC effect by comparing the adjacent peak structures.