Validation of a quantized-current source with 0.2 ppm uncertainty

TL;DR

This paper demonstrates highly accurate quantized current measurements using a tunable-barrier single-electron pump, validating the potential for a quantum current standard with unprecedented precision.

Contribution

It introduces a new picoammeter instrument and confirms current quantization at 0.2 ppm uncertainty, surpassing previous standards and validating future quantum current standards.

Findings

Confirmed quantized current at 545 MHz with 0.2 ppm uncertainty

Improved measurement accuracy by a factor of 5 over previous work

Validated the potential of single-electron transport for quantum current standards

Abstract

We report on high-accuracy measurements of quantized current, sourced by a tunable-barrier single-electron pump at frequencies $f$ up to $1$ GHz. The measurements were performed with a new picoammeter instrument, traceable to the Josephson and quantum Hall effects. Current quantization according to $I=ef$ with $e$ the elementary charge was confirmed at $f=545$ MHz with a total relative uncertainty of 0.2 ppm, improving the state of the art by about a factor of 5. For the first time, the accuracy of a possible future quantum current standard based on single-electron transport was experimentally validated to be better than the best realization of the ampere within the present SI.