Towards a quantum representation of the ampere using single electron pumps

TL;DR

This paper demonstrates a semiconductor quantum dot electron pump with significantly improved accuracy, capable of generating a high current close to a billion electrons per second, advancing towards a quantum standard of the ampere.

Contribution

It introduces specially designed gate drive waveforms that dramatically enhance the accuracy of semiconductor quantum dot electron pumps.

Findings

Current accuracy better than 1.2 ppm experimentally

Evidence suggests true accuracy approaching 0.01 ppm

Pump generates up to 150 pA, nearly a billion electrons per second

Abstract

Electron pumps generate a macroscopic electric current by controlled manipulation of single electrons. Despite intensive research towards a quantum current standard over the last 25 years, making a fast and accurate quantised electron pump has proved extremely difficult. Here we demonstrate that the accuracy of a semiconductor quantum dot pump can be dramatically improved by using specially designed gate drive waveforms. Our pump can generate a current of up to 150 pA, corresponding to almost a billion electrons per second, with an experimentally demonstrated current accuracy better than 1.2 parts per million (ppm) and strong evidence, based on fitting data to a model, that the true accuracy is approaching 0.01 ppm. This type of pump is a promising candidate for further development as a realisation of the SI base unit ampere, following a re-definition of the ampere in terms of a fixed value of the elementary charge.