ABSTRACT
A material called LK-99, a modified-lead apatite crystal structure with the composition Pb10−xCux(PO4)6O (0.9<x<1.1), has been synthesized using the solid-state method. The material exhibits the Ohmic metal characteristic of Pb(6s1) above its superconducting critical temperature, Tc, and the levitation phenomenon as Meissner effect of a superconductor at room temperature and atmospheric pressure below Tc. A LK-99 sample shows Tc above 126.85∘C (400 K). We analyze that the possibility of room-temperature superconductivity in this material is attributed to two factors: the first being the volume contraction resulting from an insulator-metal transition achieved by substituting Pb with Cu, and the second being on-site repulsive Coulomb interaction enhanced by the structural deformation in the one-dimensional(D) chain (Pb2-O1/2-Pb2 along the c-axis) structure owing to superconducting condensation at Tc. The mechanism of the room-temperature Tc is discussed by 1-D BR-BCS theory.
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