Parity effect in Al and Nb single electron transistors in a tunable environment

TL;DR

This study compares the parity effects in Al and Nb single electron transistors within tunable environments, revealing a clear 2e-periodicity in Al devices but not in Nb, highlighting material-dependent phenomena.

Contribution

It demonstrates the material-dependent parity effects in single electron transistors, showing Al exhibits 2e-periodicity while Nb does not under similar conditions.

Findings

Al transistors show gate charge modulation with 2e-periodicity

Nb transistors do not exhibit 2e-periodicity under similar conditions

Material properties influence parity effects in superconducting transistors

Abstract

Two different types of Cooper pair transistors, with Al and Nb islands, have been investigated in a tunable electromagnetic environment. The device with an Al island demonstrates gate charge modulation with 2e-periodicity in a wide range of environmental impedances at bath temperatures below 340 mK. Contrary to the results of the Al sample, we were not able to detect 2e-periodicity under any conditions on similar samples with Nb island. We attribute this to the material properties of Nb.