[Submitted on 1 Aug 2023]

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Abstract: A recent paper [Lee {em et al.}, J. Korean Cryt. Growth Cryst. Techn. {bf
33}, 61 (2023)] provides some experimental indications that
Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O with $xapprox 1$, coined LK-99, might be a
room-temperature superconductor at ambient pressure. Our density-functional
theory calculations show lattice parameters and a volume contraction with $x$
— very similar to experiment. The DFT electronic structure shows Cu$^{2+}$ in
a $3d^9$ configuration with two extremely flat Cu bands crossing the Fermi
energy. This puts Pb$_{9}$Cu(PO$_4$)$_6$O in an ultra-correlated regime and
suggests that, without doping, it is a Mott or charge transfer insulator. If
doped such an electronic structure might support flat-band superconductivity or
an correlation-enhanced electron-phonon mechanism, whereas a diamagnet without
superconductivity appears to be rather at odds with our results.

Submission history

From: Liang Si [view email]


Tue, 1 Aug 2023 17:21:48 UTC (1,572 KB)

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