Absence of Superconductivity in Cu Doped Lead Apatite*

We report on the structural, electrical and magnetic measurements in as-grown polycrystalline samples of Pb₁₀(PO₄)₆O and Cu doped Pb_10-xCu_x(PO₄)₆O.  The copper doped compound has been recently claimed to be a superconductor at room temperature. Structural characterizations (XRD, TEM, Raman) data are analyzed . This sample has 1.5% of Cu₂S as an impurity phase. No evidence of superconductivity is observed either in resistivity measurements or in magnetization measurements. A resistive transition with thermal hysteresis around 380 K is observed, which can be associated with possible structural transition of Cu₂S. Hall measurements provide evidence of hole doping through Cu substitution. The obtained value of band gap (E_g= 0.51eV) indicates that the obtained Cu doped sample is semiconducting.  In conclusion, we find no evidence for superconductivity in Cu doped lead apatite Pb₉Cu(PO4)₆O at ambient pressure.