Today’s superconductors usually only function when cooled to incredibly low temperatures. Kiyoshi Takahase Segundo / Alamy Stock Photo

It would be unfair to call it a philosopher’s stone, yet there is something beguiling about the search for a room-temperature superconductor. This material would be able to transmit electricity perfectly, without any resistance. It could pick up renewable energy where it is abundant and deliver it efficiently to faraway cities, going a long way towards solving the climate crisis.

No wonder, then, that when not one, but two such materials were supposedly discovered last year, the physics world went into a frenzy. In March 2023, researchers reported a material known as “red matter” that could purportedly do the business at 21°C (70°F), albeit only at incredible pressures. A matter of weeks later, news broke of another substance called LK-99 that apparently worked at both room temperature and ambient pressure. Alas, all that glitters is not gold – both claims have now been widely dismissed.

But the fuss over those studies obscures a more subtle and interesting truth: broader research in pursuit of a practical superconductor is racing forwards and there is a sense that, finally, the search is turning a corner. In the past few years, there have been more experimental breakthroughs than you can shake a stick at, while theorists are honing a wealth of methods to predict…