In this study, we re-evaluated the superconducting properties of LK-99. The LK-99 samples were synthesized using the process proposed by the original Korean team. Additionally, we examined whether the results of the Korean team are related to Cu2S by using ammonia solution (NH3-H2O) to remove Cu2S . Through x-ray diffraction (XRD) analysis, a distinct Cu2S phase was identified in the LK-99 samples. A subsequent treatment using an ammonia solution effectively eliminated this phase. The appearance of blue Cu+2 ions in the solution and the elimination of the Cu2S peak in XRD support the conclusion. The magnetic and electrical properties of LK-99 with and without Cu2S postulate that the superconducting-like behavior in LK-99 predominantly arises from a transition in resistivity due to the influence of Cu2S . As such, LK-99 is better classified as a diamagnetic semiconductor than a room-temperature superconductor. The room-temperature superconductors still require further research.
@article{arxiv.2309.17445,
title = {The characteristics of LK-99 by Cu$_2$S removal using ammonia solution: A diamagnetic semiconductor},
author = {Zhujialei Lei and Chin-Wei Lin and I-Nan Chen and Chun-Tse Chou and Li-Min Wang},
journal= {arXiv preprint arXiv:2309.17445},
year = {2023}
}