Data | The quest for a room-temperature superconductor is not without resistance Premium

The decades-long search for a room-temperature and ambient-pressure superconductor has been arduous, spanning technologies, materials, and theories

On July 21, a group of physicists in South Korea reported that they had synthesised a material that was a superconductor at room temperature and ambient pressure. Scientists have been looking for such a material for decades now — a substance that can carry an electric current with zero losses. A not insignificant amount of electric current is lost today during transmission between a power plant and the point of consumption. A room-temperature superconductor would also bring considerable gains for heavy industrial and research applications, including medical diagnostics, mass spectrometers, nuclear reactor designs, and particle colliders. But has the South Korean group really found such a thing?

Superconductivity research is more than a century old and has developed in tandem with technologies to cool materials to very low temperatures and/or apply very high pressures and techniques to understand whether a material has really become superconducting at the microscopic scale. Both are highly sophisticated enterprises with very small margins of error.

Chart 1 | The chart shows the materials ordered by their critical temperature (Tc), the temperature below which they become superconducting (in kelvin)

Tc values vary depending on the material’s properties. Values here are indicative.

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The jump between magnesium diboride and YBCO, and up to HBCCO, is the result of a revolution in the late 1980s when physicists discovered the higher-temperature copper-oxide superconductors. The value of Tc makes the difference between cooling the material with liquid helium, which is relatively more difficult, and with liquid nitrogen. Copper-oxides can be cooled with liquid nitrogen to their Tc values. While this chart also shows LaH10 to be a room-temperature superconductor, there is a catch: it is one of a few materials that scientists found to become superconducting at or near room temperature but under enormous pressure (Chart 2).

Chart 2 | The chart shows the pressure required to induce a superconducting state in some materials. (Yellow) shows the critical pressure and (blue) shows the critical temperature.