A “possible real solution to the energy crisis” that “could change everything”. That’s how recent headlines billed the mundane lumps of a dirty-looking material known as LK-99 reported by scientists in South Korea in July. Their findings were described in two papers (https://arxiv.org/abs/2307.12008 and https://arxiv.org/abs/2307.12037) posted to the arXiv preprint server – a website where researchers present work that has not yet been subjected to peer review. They said they had “for the first time in the world” made a superconductor that worked at room temperature and at everyday pressure.
A superconductor is a material that can conduct an electric current without any resistance, meaning that no energy is lost through heat. Superconductors have been known about for more than 100 years, but previous ones have worked only at extremely low temperatures or when under very high pressures. LK-99 on the other hand, the South Korean team said, was superconductive just sitting there on a benchtop. If they had been right, the discovery would genuinely have merited the word “revolutionary”.
But after weeks of feverish speculation and frantic attempts worldwide to make and test the new material, many experts in the normally recondite field of solid-state physics now think the claims were almost certainly wrong. There was reason to be sceptical from the outset: the South Korean scientists, Sukbae Lee and Ji-Hoon Kim of the Seoul-based startup company Quantum Energy Research Center had no track record in the field, and LK-99 – named after them and the year they began studying it – didn’t look much like high-temperature superconductors seen in the past.
A broad consensus is now emerging that the apparent signatures of superconductivity the Korean team reported – zero-resistance and a magnetic phenomenon called the Meissner effect – may have more mundane explanations. But even if LK-99 is a blind alley, the quest for a wonder material that is superconductive under everyday conditions will continue.
“It will happen,” says the physicist Jorge Hirsch of the University of California San Diego, “although it is hard to tell when.” But when it does, he says, it will result in “all sorts of incredible applications we haven’t even imagined yet”.
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