Most superconductors only superconduct at temperatures near absolute zero, but about 20 years ago, it was discovered that some ceramics can superconduct at higher temperatures (but usually still below 100 Kelvin, or -173 Celsius). Such high-temperature superconductors are now beginning to be used for many applications, including cell-phone base stations and a demo magnetic-levitation train. But their potential applications could be much broader. “If you could make superconductors work at room temperature, then the applications are endless,” said Hudson.

Superconductors are superior to ordinary metal conductors such as copper because current doesn’t lose energy as wasteful heat as it flows through them, thus allowing larger current densities. Once a current is set in motion in a closed loop of superconducting material, it will flow forever.
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The new MIT study shows that scattering by impurities occurs in the pseudogap state as well as the superconducting state. That finding challenges the theory that the pseudogap is only a precursor state to the superconductive state, and offers evidence that the two states may coexist.

This method of comparing the pseudogap and superconducting state using STM could help physicists understand why certain materials are able to superconduct at such relatively high temperatures, said Hudson. “Trying to understand what the pseudogap state is is a major outstanding question,” he said.