Andreev tunneling in charge pumping with SINIS turnstiles

TL;DR

This paper investigates how Andreev tunneling affects the performance of hybrid SINIS turnstiles used for charge pumping, demonstrating the suppression of Andreev current with increased charging energy through experiments and simulations.

Contribution

It provides experimental measurements and numerical analysis of Andreev tunneling effects in SINIS turnstiles, highlighting how charging energy influences tunneling rates.

Findings

Andreev tunneling impacts current plateau characteristics.

Numerical simulations accurately model the observed effects.

Higher charging energy suppresses Andreev current.

Abstract

We present measurements on hybrid single-electron turnstiles with superconducting leads contacting a normal island (SINIS). We observe Andreev tunneling of electrons influencing the current plateau characteristics of the turnstiles under radio-frequency pumping. The data is well accounted for by numerical simulations. We verify the dependence of the Andreev tunneling rate on the turnstile's charging energy. Increasing the charging energy effectively suppresses the Andreev current.