The First Room-Temperature Ambient-Pressure Superconductor

TL;DR

This paper reports the synthesis of the first room-temperature superconductor, LK-99, functioning at ambient pressure with a critical temperature of at least 400 K, achieved through structural distortion caused by Cu substitution.

Contribution

It introduces a novel superconductor, LK-99, demonstrating room-temperature superconductivity at ambient pressure due to minute structural distortions and interface quantum wells.

Findings

Superconductivity confirmed by critical temperature, zero-resistivity, and Meissner effect.

Superconductivity originates from structural distortion caused by Cu substitution.

LK-99 maintains superconductivity at room temperature and ambient pressure.

Abstract

For the first time in the world, we succeeded in synthesizing the room-temperature superconductor ($T_c \ge 400$ K, 127$^\circ$C) working at ambient pressure with a modified lead-apatite (LK-99) structure. The superconductivity of LK-99 is proved with the Critical temperature ($T_c$), Zero-resistivity, Critical current ($I_c$), Critical magnetic field ($H_c$), and the Meissner effect. The superconductivity of LK-99 originates from minute structural distortion by a slight volume shrinkage (0.48 %), not by external factors such as temperature and pressure. The shrinkage is caused by Cu$^{2+}$ substitution of Pb$^{2+}$(2) ions in the insulating network of Pb(2)-phosphate and it generates the stress. It concurrently transfers to Pb(1) of the cylindrical column resulting in distortion of the cylindrical column interface, which creates superconducting quantum wells (SQWs) in the interface. The heat capacity results indicated that the new model is suitable for explaining the superconductivity of LK-99. The unique structure of LK-99 that allows the minute distorted structure to be maintained in the interfaces is the most important factor that LK-99 maintains and exhibits superconductivity at room temperatures and ambient pressure.