Graphene based electron pipe may lead to more accurate ampere definition

Researchers from the National Physical Laboratory (the NPL) and the University of Cambridge wants to redefine the ampere, using the world's first graphene single-electron pump (SEP).

The idea is to redefine the ampere in terms of the electron charge. The SEP creates a flow of individual electrons by shutting them in a quantum dot and then emitting them one at a time at a well-defined rate. The researchers managed to produce such a pump for the first time, and this can provide the speed of electron flow - which can be used to redefine the ampere.

Accurate SEPs were made before, but the speed was too slow. The breakthrough came by using graphene which can turn the quantum dot on and off very quickly (at near gigahertz frequency).

The new SEP made by the researchers is still not optimized enough, but hopefully they will continue to work and improve it to be useful for ampere definition.

Posted: May 15,2013 by Ron Mertens