Accurate high speed single-electron quantum dot preparation

TL;DR

This paper demonstrates high-precision single-electron transfer in a GaAs quantum dot pump with accuracy better than 15 ppm, advancing quantum device reliability and potential quantum computing applications.

Contribution

It provides the first high-accuracy measurement of electron transfer in a GaAs quantum dot pump, highlighting its potential for quantum standards and computing.

Findings

Electron transfer accuracy better than 15 ppm.

Dependence of pump current on tuning parameters analyzed.

Possible deviations from existing pumping cycle models.

Abstract

Using standard microfabrication techniques it is now possible to construct devices, which appear to reliably manipulate electrons one at a time. These devices have potential use as building blocks in quantum computing devices, or as a standard of electrical current derived only from a frequency and the fundamental charge. To date the error rate in semiconductor 'tuneable-barrier' pump devices, those which show most promise for high frequency operation, have not been tested in detail. We present high accuracy measurements of the current from an etched GaAs quantum dot pump, operated at zero source-drain bias voltage with a single AC-modulated gate driving the pump cycle. By comparison with a reference current derived from primary standards, we show that the electron transfer accuracy is better than 15 parts per million. High-resolution studies of the dependence of the pump current on the quantum dot tuning parameters also reveal possible deviations from a model used to describe the pumping cycle.