Published in Physics World, 11 Mar 2009
Physicists in the US have shown how the electrical current flowing through certain molecular junctions can be switched on and off on by simply stretching or compressing the molecules. The discovery could be exploited to make switches in future molecular devices, and could also help in the understanding of resistance at the nanoscale.
In normal electronic devices, resistance is a well-understood property. When an electric field is applied across a metal, charge–carrying electrons begin to drift but bump into ions and impurities, which slow their motion. At nanometre distances, however, things are not so simple: electrons are able to “tunnel” across small insulating barriers with a finite probability. This means that the electrons can overcome obstacles without losing energy, and therefore without electrical resistance. […]
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