Dragging single electrons

Abstract

Controlled transfer of single electrons in nanoscale devices allows electric curent to be measured in fundamental units of charge and frequency. a new silicon device promises to make these standards more practical. Comment This short overview about electrical current measurement for reproducing the unit ampere descibes the approach of A. Fujiwara and Y. Takahashi, Nature 2001, 410, 560 - 562 which may allow an accuracy of better than 10(-10) (already standard for time, voltage, frequency) in the future