What Is LK-99? The Room-Temperature Superconductor Claim, Explained
Have you ever wondered why the name of this blog keeps showing up in searches for a "room-temperature superconductor"? LK-99 is not a superconductor. It is a copper-doped lead compound that a Korean research team claimed in July 2023 could carry electricity with zero resistance at room temperature — and within 25 days, independent labs showed the claim was wrong. This is the full story, the numbers behind the verdict, and where the real search stands in 2026. What LK-99 Is — and What Was Claimed LK-99 is a copper-doped lead oxyapatite, roughly Pb9Cu(PO4)6O. The name comes from the initials of Sukbae Lee and Ji-Hoon Kim, the Korea University researchers who led the work, and 99 for 1999, the year they began studying the material. On 22 July 2023, the team posted two preprints on arXiv claiming LK-99 was "the first room-temperature ambient-pressure superconductor," with a critical temperature up to 400 K — that is 127 °C, hotter than boiling water — at ordinary p...