Physics: Room-temperature superconductivity

The observation of room-temperature superconductivity in hydride, a hydrogen-rich compound derived from organic components under high pressure, is reported in Nature this week. This discovery represents a step towards the long-sought goal of creating electrical systems with perfect efficiency.

Superconductivity is a phenomenon whereby electrical energy can move through a material without resistance. This effect was first observed at temperatures close to absolute zero. Achieving superconductivity at room temperature has the potential to improve the efficiency of electrical conductors and devices by minimizing the generation of heat.

Hydrogen-rich materials under high pressure have been shown to increase the temperatures at which superconductivity can be demonstrated, to around minus 23 degrees Celsius. The latest work by Ranga Dias and colleagues raises the temperature at which a zero-resistance state is achieved to 15 degrees Celsius. This effect is observed in a photochemically synthesized ternary carbonaceous sulfur hydride system at pressures of 267 billion pascals — this pressure is about a million times higher than a typical tyre pressure. In their system, laser light and pressure are used to transform elemental precursors (carbon, sulphur and molecular hydrogen) into the superconducting material. The critical temperature at which the material becomes superconducting increases with pressure, up to the highest pressure values achieved in the experiment.

The next goal will be the observation of room-temperature superconductivity at ambient pressure. Chemical tuning of the system could help to lower the required pressure, the authors say.