Single-electron turnstile pumping with high frequencies

TL;DR

This paper provides a theoretical analysis of single-electron turnstile operation at various frequencies, revealing conditions for effective pumping and the emergence of fractional electron transfer due to quantum coherence.

Contribution

It introduces a theoretical framework for understanding high-frequency single-electron pumping and identifies the transition to fractional pumping caused by quantum coherence effects.

Findings

Turnstile operates below a characteristic frequency determined by tunneling rates.

Fractional electron pumping occurs at frequencies above the characteristic frequency.

Quantum coherence influences electron transfer at high frequencies.

Abstract

In this Letter, we present a theoretical analysis to single-electron pumping operation in a large range of driving frequencies through the time-dependent tunneling barriers controlled by external gate voltages. We show that the single-electron turnstile works at the frequency lower than the characteristic frequency which is determined by the mean average electron tunneling rate. When the driving frequency is greater than the characteristic frequency of electron tunnelings, fractional electron pumping occurs as an effect of quantum coherence tunneling.