The lure of gold can be electric to some people, even though the element is chemically inert—on the large scale. But researchers from Georgia Tech report that, down at the level of atoms, gold can conduct electricity and act as an insulator as well.
When an oxygen molecule is embedded into six atom-long gold wire, the wire can conduct electricity. But, when the wire is longer than six atoms, the oxygenated gold becomes an insulator. The scientists reported their discovery in the journal Physical Review Letters.
The researchers say these properties mean that gold nanowires might be used as sensors to detect motion in nanoscale situations such as neurons or nanomachnes (futuristic devices built from individual atoms that might enter cells and fight disease). The wire could be a sensor because when it’s extended even slightly, it could switch from a conductor to an insulator. Using gold as a sensor in this way could never have been predicted from what is known about gold in bulk. But being very small can lead to some big changes.
—Steve Mirsky, with reporting by Harvey Black