A Superinsulating State.

Observed by an Argonne-Novovsibirsk-Regensburg-Bochum collaboration in titanium-nitride films, is the antithesis of the superconducting state. In conventional superconductivity electrons pair up, and these pairs enter into a single quantum state in which current flows with zero electrical resistivity. By contrast, the titanium-nitride film studied here, while normally a superconductor at low temperatures, can be forced to become an insulator. Under a combination of conditions-the sample being a certain thickness and an external magnetic field being present-the lowering of temperature can actually reverse the electrical property of the material from one of zero resistivity to one of zero conductivity: in other words a perfect superinsulator. (Vinokur et al., Nature 3 April 2008).