In mid-2023, a South Korean group reported that a modified lead-apatite material, LK-99, exhibited superconductivity at room temperature and ambient pressure. Because all established superconductors require cryogenic cooling or extreme pressure, an ambient-condition superconductor would carry enormous technological implications. The claim propagated rapidly, amplified by a widely shared video showing a fragment of the sample partially levitating over a magnet.
Independent replication began almost immediately. More than a dozen laboratories were unable to reproduce superconductivity, and several characterised the material as an insulator. Analysts attributed the partial levitation to ordinary ferromagnetism or diamagnetism rather than the flux expulsion characteristic of a superconductor, and traced a reported resistance drop to a copper sulfide (Cu2S) impurity, which undergoes a structural transition near 400 kelvin and can produce a superficially similar signal. The reported synthesis was also difficult to reproduce, with an under-specified composition.
By late 2023, the consensus had settled that LK-99 is not a room-temperature superconductor. The case is frequently cited as an illustration of self-correction in science. It shows the value of the maxim that extraordinary claims require extraordinary evidence, the central role of independent replication, and the risk of treating a single dramatic observation, propagated through social media ahead of scrutiny, as if it were established fact. Notably, the process worked: open, rapid replication resolved the question within months.