Abstract

Electron pumps transport an integer number of electrons between source and drain leads in response to a periodic control voltage. Even before the first demonstration of metallic electron pumps in the early 1990s, pumps were mooted as a new way of defining the ampere, the unit of electric current and one of the seven base units in the SI system.

This talk will briefly review historical efforts to realise accurate electron pumps before focussing on the recent work of a NPL -Cambridge collaboration, which demonstrated 1 part-per-million accuracy in a quantum dot pump clocked at 945 MHz [1]. This record combination of speed and accuracy was made possible by driving the pump with a specially designed waveform. Prospects for improving the accuracy will be discussed, in the context of the likely future re-definition of the SI unit ampere in terms of a fixed value of the electron charge.

[1] S. P. Giblin et al., Towards a quantum representation of the ampere using single electron pumps, Nature Communications 3 (930) (2012)