Role of Oxygen States in the Low Valence Nickelate La$_4$Ni$_3$O$_8$
| Autor: | 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. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Phys. Rev. X 12, 011055 (2022) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevX.12.011055 |
| Popis: | 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. Comment: 13 pages; to appear in PRX |
| Databáze: | arXiv |
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