Quantized current of a hybrid single-electron transistor with superconducting leads and a normal-metal island

TL;DR

This paper explores the operation of a hybrid SINIS single-electron transistor that achieves current quantization with minimal control, analyzes error mechanisms, and presents experimental results showing improved leakage current performance.

Contribution

It introduces the SINIS turnstile as a quantum current standard and provides experimental evidence of its improved leakage current over previous designs.

Findings

Demonstrated current quantization with a single rf control parameter.

Identified main error mechanisms affecting the turnstile.

Showed decreased leakage current in experimental measurements.

Abstract

We discuss the operation of the superconductor - insulator - normal-metal - insulator - superconductor (SINIS) turnstile. This voltage-biased hybrid single-electron transistor (SET) provides current quantization even with only one radio-frequency (rf) control parameter, namely the gate voltage of the single island. We give an overview of the main error mechanisms of the turnstile and consider its feasibility as a quantum current standard. We also present experimental results of pumping with the SINIS structure which show decreased leakage current compared to earlier measurements with the opposite NISIN structure.