In 1968, physicist Neil Ashcroft predicted that pure hydrogen would condense under extreme pressure into a superconducting metal capable of surviving at room temperature. Not many believed him, but the possibility of room temperature superconductivity inspired a few intrepid researchers.
Attitudes changed in 2015 when physicist Mikhail Eremets discovered a compound of hydrogen and sulfur that was superconductive up to -70 oC (-94 oF) when extreme pressure was applied. The work inspired a wave of research on room-temperature superconductivity with hydrogen compounds.
In a recent study published in Nature, a group of physicists reported superconductivity at room temperature and extreme pressure by adding a third element — carbon — to Eremet’s original compound of hydrogen and sulfur. They chose to use carbon because its strong bonds could help keep a material together once the pressure is released as it does for diamond.
The researchers compressed their mix of elements between the microscopic tips of two pointy diamonds. The final result was a superconducting temperature of 15 oC (58 oF) at 267 gigapascals, the same pressure that you would experience if you traveled about three-fourths of the way to the center of the Earth.
While they knew the chemical elements that made up the superconductor, the extreme pressure prevented their probes from obtaining data on the material’s final molecular and crystal structure. Until these are determined, researchers will face difficulty developing models that explain the high superconducting temperature measured.
Since the new superconductor requires extreme pressure, it also currently lacks immediate practical applications. Yet, the study suggests that a variation could prove useful, sparking new enthusiasm among researchers. The fantasies of ultra-efficient energy generation, perfect energy storage, and lossless power transmission are much closer to reality.