Entertaining the Possibility of RT Superconductivity in LK-99

Abstract

An intuitive chemical perspective on the LK-99 material is outlined and supported by DFT calculations. A hidden flat Lead band that exhibits instability toward charge density wave formation is exposed. Electron transfer between Lead CDW/conduction bands and Cu$_3$d$^9$/Cu$_3$d$^{10}$ impurity states is suggested to embody the observed phenomenology reminiscent of room temperature superconductivity. The inter-system electronic instability is reflected in a chemical instability involving 2Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O => Pb$_{20-2x}$Cu$_{2x}$(PO$_4$)$_{12}$(O$_2$). Implications for tuning posttreatments as well as handling of the LK-99 material emerge.