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Role of Oxygen States in the Low Valence Nickelate La$_4$Ni$_3$O$_8$

Authors :
Shen, Y.
Sears, J.
Fabbris, G.
Li, J.
Pelliciari, J.
Jarrige, I.
He, Xi
Bozovic, I.
Mitrano, M.
Zhang, Junjie
Mitchell, J. F.
Botana, A. S.
Bisogni, V.
Norman, M. R.
Johnston, S.
Dean, M. P. M.
Publication Year :
2021
Publisher :
arXiv, 2021.

Abstract

The discovery of superconductivity in square-planar low valence nickelates has ignited a vigorous debate regarding their essential electronic properties: Do these materials have appreciable oxygen charge-transfer character akin to the cuprates, or are they in a distinct Mott-Hubbard regime where oxygen plays a minimal role? Here, we resolve this question using O $K$-edge resonant inelastic x-ray scattering (RIXS) measurements of the low valence nickelate La$_{4}$Ni$_{3}$O$_{8}$ and a prototypical cuprate La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x=0.35$). As expected, the cuprate lies deep in the charge-transfer regime of the Zaanen-Sawatzky-Allen scheme. The nickelate, however, is not well described by either limit of the ZSA scheme and is found to be of mixed charge-transfer/Mott-Hubbard character with the Coulomb repulsion $U$ of similar size to the charge-transfer energy $\Delta$. Nevertheless, the transition-metal-oxygen hopping is larger in La$_{4}$Ni$_{3}$O$_{8}$ than in La$_{2-x}$Sr$_{x}$CuO$_{4}$, leading to a significant superexchange interaction and an appreciable hole occupation of the ligand O orbitals in La$_{4}$Ni$_{3}$O$_{8}$ despite its larger $\Delta$. Our results clarify the essential characteristics of low valence nickelates and put strong constraints on theoretical interpretations of superconductivity in these materials.<br />Comment: 13 pages; to appear in PRX

Details

Database :
OpenAIRE
Accession number :
edsair.doi.dedup.....001000778b82d95b24629fea17b724af
Full Text :
https://doi.org/10.48550/arxiv.2110.08937