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

We study superconducting pairing correlation (SPC) effect on low-temperatur e electron transport through a single electron transistor containing an ult rasmall superconducting grain with a gate electrode. It is shown that the S PC 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 w hich are equivalent each other if the SPC is completely negligible. It is s hown that the two peak structures could differ from each other due to the S PC in actual experimental situations. This indicates that we can detect the SPC effect by comparing the adjacent peak structures. (C) 2001 Elsevier Sc ience B.V. All rights reserved.