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Ihor Sukhenko

Publications and source records attributed to Ihor Sukhenko.

2 recordsLinked to original sources
arXiv2025

Correlated electronic structure and local spin in lead-copper-vanadium-bromine apatite: a DMFT study

We study the correlated electronic structure and local spin behaviour of the copper-substituted lead-vanadium bromine apatite Pb$_9$Cu(VO$_4$)$_6$Br$_2$ using DFT+DMFT with a two-orbital Cu-centred low-energy model. Simulations are done for several temperatures (20, 60, 100 K) and a broad range of band fillings 2.46 $\leq$ n $\leq$ 3.54. We find that the present compound stays metallic even once correlations are treated dynamically around the stoichiometric filling (n $\simeq$ 3). Away from n $\simeq$ 3, both hole and electron doping drive the system toward non-Fermi-liquid behaviour, and spectral weight is transferred from the low-energy peak into upper and lower Hubbard-like features. By analysing the low-frequency self-energy exponent and the dynamical part of the local spin susceptibility, we identify a narrow window of enhanced spin fluctuations on the slightly hole-doped side (n $\simeq$ 2.94), i.e. a spin-freezing-crossover regime of the kind reported in the literature for multiorbital Hund metals. This places Pb$_9$Cu(VO$_4$)$_6$Br$_2$ among the promising members of the Cu-substituted apatite family.

cond-mat.str-el↗
arXiv2025

Climbing the ladder: a method for identifying promising copper-lead apatites

We develop a DFT screening procedure for copper-substituted lead apatites of the composition Pb$_9$Cu(XO$_4$)$_6$Y that enforces three design rules: thermodynamic stability, Cu site preference, and symmetry robustness of the near-Fermi electronic structure. A convex-hull analysis over P/V/As as X, O/F/Cl/Br as Y, identifies vanadates as the only members on or beneath the hull. Across the family, Cu substitution at Pb$^{\text{I}}$ ($4f$) preserves flat bands at E$_F$, whereas Pb$^{\text{I}}$ ($6h$) either gaps or severely distorts them. Small symmetry-lowering relaxations ($P3 \rightarrow P1$) are also capable of opening the band gap, motivating symmetry robustness as a filter. Applying these criteria singles out Pb$_9$Cu(VO$_4$)$_6$Br$_2$ (and, possibly, Cl$_2$) as leading candidates. This work motivates experimental study of the selected compounds, as well as a dedicated study of strong correlations.

cond-mat.str-el↗