Absence of superconductivity in LK-99 at ambient conditions

TL;DR

This study thoroughly synthesized phase-pure LK-99 and found no evidence of superconductivity at room temperature, contradicting earlier claims, supported by experimental and computational analyses.

Contribution

It provides a comprehensive synthesis and characterization of LK-99, demonstrating the absence of superconductivity at ambient conditions through experimental and theoretical methods.

Findings

LK-99 is diamagnetic at 280 K with no superconducting signatures.

Synthesized LK-99 shows phase purity confirmed by PXRD and Rietveld refinement.

Electronic structure calculations indicate strong correlations but no superconductivity.

Abstract

The report of synthesis of modified Lead apatite (LK-99) with evidence of superconductivity at more than boiling water temperature has steered the whole scientific community. There have been several failures to reproduce superconductivity in LK-99 including partial successes. Here, we have continued our efforts to synthesize phase pure LK-99 with improved precursors. The process has been followed as suggested by Sukbae Lee et. al., [1,2]. The phase purity of each precursor is evidenced by Powder X-ray diffraction (PXRD) and well fitted by Rietveld refinement. The PXRD confirms the synthesis of phase pure polycrystalline LK-99 with apatite structure. The freshly synthesized sample does not show any signature of superconductivity levitation on a magnet (diamagnetism). The magnetization measurements on SQUID also show that LK-99 is diamagnetic at 280 K, there is no sign of superconductivity in LK-99 at room temperature. Moreover, we have also performed first principle calculations to investigate the electronic band structure of the LK-99 near Fermi level. Our study verifies that the Cu doped lead apatite (LK-99) has bands crossing at Fermi level, indicating generation of strong correlation in the system.