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arXiv · 2311.06053

Revisiting the metal-to-metal transition in $2H$-AgNiO$_2$

Jannik Gondolf·Ilya Eremin·Frank Lechermann
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Abstract

The layered delafossite compound AgNiO$_2$ with $2H$ stacking symmetry undergoes a structural metal-to-metal transition at $T_{\rm S}\sim 365$ K. It has been described in the past as a charge-ordering transition, where local $S=1$ spins are formed on part of the Ni sites. By means of first-principles many body calculations, we show that the transition is in fact a site-selective Mott transition on the Ni sublattice with only minor charge differentiation. Key to this finding is the uncovering of ligand-hole physics, rendering a Ni$^{2+}$ instead of a formal Ni$^{3+}$ oxidation state, in conjunction with strong local Coulomb repulsions.

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Jannik Gondolf, Ilya Eremin, Frank Lechermann. 2023-11-10. Revisiting the metal-to-metal transition in $2H$-AgNiO$_2$. https://doi.org/10.1209/0295-5075%2Fad0d1d

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