‘Tantalizing’ Hints of Room-Temperature Superconductivity
Researchers in Germany have claimed a breakthrough: a material that can act as a superconductor — transmit electricity with zero resistance — at room temperature and above. Superconductors offer huge potential energy savings, but until now have worked only at temperatures of lower than about -110 °C.
Now, Pablo Esquinazi and his colleagues at the University of Leipzig report that flakes of humble graphite soaked in water seem to continue superconducting at temperatures of greater than 100 °C1. Even Esquinazi admits that the claim “sounds like science fiction”, but the work has been published in the peer-reviewed journal Advanced Materials, and other physicists contacted by Nature say that the results, although tentative, merit further scrutiny.
Graphite, which consists of layers of carbon atoms arranged in hexagonal lattices, can superconduct when doped with elements that provide it with additional free electrons. Calcium graphite, for example, superconducts at up to 11.5 kelvin (about -260 °C)2, and theorists have predicted that temperatures of up to 60 kelvin could be reached if enough free electrons were available.
Esquinazi’s team speculates that high concentrations of electrons form at the interfaces between neighbouring thin segments of graphite. Having already observed superconductivity at more than 100 kelvin at the interfaces within an artificial type of bulk graphite known as pyrolytic graphite3, the researchers wondered whether they could reach even higher temperatures by doping flakes of graphite powder.