Zero-average bias bidirectional single-electron current generation in a hybrid turnstile

TL;DR

This paper introduces a method to generate accurate single-electron currents in a hybrid turnstile without any average bias voltage by using a specially modulated source signal, enabling bias-free electron control.

Contribution

It demonstrates a novel zero-average bias operation mode for hybrid turnstiles using a phase-shifted, frequency-doubled source modulation, expanding the control capabilities of single-electron devices.

Findings

Accurate single-electron currents achieved at zero average bias.

Current direction controlled by phase shift of source modulation.

Operation does not require non-zero DC bias voltage.

Abstract

Hybrid turnstiles have proven to generate accurate single-electron currents. The usual operation consists of applying a periodic modulation to a capacitively coupled gate electrode and requires a non-zero DC source-drain bias voltage. Under this operation, a current of the same magnitude and opposite direction can be generated by flipping the polarity of the bias. Here, we demonstrate that accurate single-electron currents can be generated under zero average bias voltage. We achieve this by applying an extra periodic modulation with twice the frequency of the gate signal and zero DC level to the source electrode. This creates a time interval, which is otherwise zero, between the crossings of tunnelling thresholds that enable single-electron tunnelling. Furthermore, we show that within this operation the current direction can be reversed by only shifting the phase of the source signal.