Room-temperature superconductivity has long been the holiest of holy grails in condensed-matter physics. Within the past decade, the appearance of new materials that superconduct at relatively balmy temperatures, but only under extreme pressures, has brought a slight yet significant alteration in the quest. To be truly grail-like, a newly synthesized superconductor cannot merely carry electrical current without resistance at room temperature. It must also do it at ambient pressure for it to have practical applications beyond the laboratory – such as levitating trains, efficient power lines or cheaper MRI machines.

So when a paper entitled “The First Room-Temperature Ambient-Pressure Superconductor” appeared on the arXiv preprint server earlier this week, physicists were intrigued – though also sceptical, given recent retractions and allegations of scientific misconduct in the field.

In the paper, Sukbae Lee and Ji-Hoon Kim, both materials scientists at the Quantum Energy Research Centre (Q-Centre) in Seoul, Korea, together with Young-Wan Kwon of Korea University, report that under everyday conditions, a modified form of the mineral lead apatite exhibits tell-tale signs of superconductivity. These signs include the all-important resistance-free flow of current; the expulsion of magnetic field from the material via the Meissner effect; and a critical temperature and critical magnetic field below which the superconducting transition occurs.

To bolster these claims, a further paper appeared shortly afterwards on the arXix, this time written by Lee and Kim in collaboration with their Q-Centre colleagues Sungyeon Im, SooMin An and Keun Ho Auh, plus Hyun-Tak Kim, a physicist at the College of William and Mary in the US. The timing of this paper’s appearance and its longer author list prompted intense online speculation about the team’s motives, with several commenters pointing out that a Nobel Prize (the likely reward for any confirmed discovery of room-temperature, ambient-temperature superconductivity) can only be shared by three people, not six. Speculation aside, the second paper repeats many of the jaw-dropping details of the first, while describing the material’s synthesis in more detail.

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