Entertaining the Possibility of RT Superconductivity in LK-99

TL;DR

This paper explores the potential for room-temperature superconductivity in LK-99 by analyzing its electronic structure and chemical stability through DFT calculations, suggesting possible mechanisms and implications for material tuning.

Contribution

It provides a chemical and electronic perspective on LK-99, identifying a hidden flat lead band and proposing a charge transfer mechanism related to superconductivity.

Findings

Identification of a hidden flat lead band with charge density wave instability

Proposed electron transfer mechanism involving lead and copper impurity states

Chemical instability related to specific compositional transformations

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.