Silicon charge pump operation limit above and below liquid helium temperature

TL;DR

This study demonstrates that silicon single-electron pumps maintain high accuracy up to 14 K, suggesting their suitability for quantum current standards in helium cryogenic systems, with errors limited by tunneling effects.

Contribution

It provides experimental insights into the temperature dependence of silicon charge pump accuracy, extending operational understanding above and below liquid helium temperature.

Findings

Charge pump uncertainty is tunnel limited below 14 K.

Lowering temperature further does not significantly reduce errors.

Silicon charge pumps can operate accurately in $^4$He cryogenic systems.

Abstract

Semiconductor tunable barrier single-electron pumps can produce output current of hundreds of picoamperes at sub ppm precision, approaching the metrological requirement for the direct implementation of the current standard. Here, we operate a silicon metal-oxide-semiconductor electron pump up to a temperature of 14 K to understand the temperature effect on charge pumping accuracy. The uncertainty of the charge pump is tunnel limited below liquid helium temperature, implying lowering the temperature further does not greatly suppress errors. Hence, highly accurate charge pumps could be confidently achieved in a $^4$He cryogenic system, further promoting utilization of the revised quantum current standard across the national measurement institutes and industries worldwide.