Experimental investigation of hybrid single-electron turnstiles with high charging energy

TL;DR

This paper experimentally investigates hybrid single-electron turnstiles with high charging energies, demonstrating quantized current plateaus and analyzing effects like backtunneling and drive waveform shape on performance.

Contribution

It provides new experimental insights into high charging energy hybrid turnstiles, including the impact of drive waveforms and backtunneling on current quantization.

Findings

Quantized current plateaus up to 160 pA achieved

Fast rise time waveforms suppress leakage errors

Backtunneling limits maximum pumped current

Abstract

We present an experimental study of hybrid turnstiles with high charging energies in comparison to the superconducting gap. The device is modeled with the sequential tunneling approximation. The backtunneling effect is shown to limit the amplitude of the gate drive and thereby the maximum pumped current of the turnstile. We compare results obtained with sine and square wave drive and show how a fast rise time can suppress errors due to leakage current. Quantized current plateaus up to 160 pA are demonstrated.