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In 2008 a team of physicists from Argonne National Laboratory, in Illinois, and other institutions stumbled upon an odd phenomenon. They called it superinsulation, because in many ways it was the opposite of superconductivity. Now they’ve worked out the theory behind it, potentially opening the doors to better batteries, supersensitive sensors, and strange new circuits. Superconductors lose all resistance once they fall below a certain temperature. In superinsulators, on the other hand, the resistance to the flow of electricity becomes infinite at very low temperatures, preventing any flow of electric current.

In the new study, which was funded by the U.S. Department of Energy, Hla's team examined synthesized molecules of a type of organic salt, (BETS)2-GaCl4, placed on a surface of silver. Using scanning tunneling spectroscopy, the scientists observed superconductivity in molecular chains of various lengths. For chains below 50 nanometers in length, superconductivity decreased as the chains became shorter. However, the researchers were still able to observe the phenomenon in chains as small as four pairs of molecules, or 3.5 nanometers in length.

Superconductivity is one of those nearly magical properties that seem to defy all intuition for how the physical world ought to work. In a superconductor, electric currents flow without resistance—an electron passes unimpeded through the material like a torpedo through some frictionless ocean. After discovering the phenomenon in 1911 Dutch physicist Heike Kamerlingh Onnes showed that an electric current in a closed superconducting loop of mercury would keep flowing long after the driving potential was removed; he demonstrated his discovery by carrying such a persistent current from the Netherlands to England. Since then physicists have discovered superconductors based on other metals and even ceramics. The latest entry is one rooted in a hydrocarbon, which superconducts at a relatively high temperature compared with elemental metals.