LK-99 also called PCPOSOS, is a gray–black, polycrystalline compound, identified as a copper-doped lead‒oxyapatite. A team from Korea University led by Lee Sukbae and Kim Ji-Hoon began studying this material as a potential superconductor, and in July 2023 published preprints claiming that it acted as a room-temperature superconductor at temperatures of up to 400 K at ambient pressure. From Wikipedia
