Electronic correlations in the ultranarrow energy band compound <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mtext>Pb</mml:mtext><mml:mn>9</mml:mn></mml:msub><mml:mtext>Cu</mml:mtext><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:msub><mml:mtext>PO</mml:mtext><mml:mn>4</mml:mn></mml:msub><mml:mo>)</mml:mo></mml:mrow><mml:mn>6</mml:mn></mml:msub><mml:mtext>O</mml:mtext></mml:mrow></mml:math>: A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>DFT</mml:mi><mml:mo>+</mml:mo><mml:mi>DMFT</mml:mi></mml:mrow></mml:math> study
Dmitry M. Korotin, Dmitry Y. Novoselov, А. О. Шориков, В. И. Анисимов, Artem R. Oganov
Abstract
We present results of investigations on the correlated nature of electronic states crossing the Fermi level in ${\mathrm{Pb}}_{9}\mathrm{Cu}{({\mathrm{PO}}_{4})}_{6}\mathrm{O}$ (also referred to as LK-99) obtained within the $\mathrm{DFT}+\mathrm{DMFT}$ approach. We found that the band structure in the vicinity of the Fermi level is formed by extremely narrow $\mathrm{Cu}\phantom{\rule{0.28em}{0ex}}d$ states and $p$ states of extra O weakly hybridized with each other. Coulomb correlations between $\mathrm{Cu}\phantom{\rule{0.28em}{0ex}}d$ electrons open the band gap between Cu ${d}_{xz}/{d}_{yz}$ and the extra-O $p$ states that form the top of the valence band. Our conclusion is that the extra-oxygen $p$ states play a significant role in the electronic properties and LK-99 cannot be mapped onto a two-band Hubbard model. We also conclude that doping with electrons will turn the stoichiometric ${\mathrm{Pb}}_{9}\mathrm{Cu}{({\mathrm{PO}}_{4})}_{6}\mathrm{O}$ into a metal, whereas the result of doping with holes is less certain.