@article{d4d6efe316114c2fa0f41edc30d2a9a8,
title = "Role of Oxygen States in the Low Valence Nickelate La4Ni3 O8",
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 La4Ni3O8 and a prototypical cuprate La2-xSrxCuO4 (x=0.35). As expected, the cuprate lies deep in the charge-transfer regime of the Zaanen-Sawatzky-Allen (ZSA) 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 Δ. Nevertheless, the transition-metal-oxygen hopping is larger in La4Ni3O8 than in La2-xSrxCuO4, leading to a significant superexchange interaction and an appreciable hole occupation of the ligand O orbitals in La4Ni3O8 despite its larger Δ. Our results clarify the essential characteristics of low valence nickelates and put strong constraints on theoretical interpretations of superconductivity in these materials.",
author = "Y. Shen and J. Sears and G. Fabbris and J. Li and J. Pelliciari and I. Jarrige and Xi He and I. Bo{\v Z}ovi{\'c} and M. Mitrano and Junjie Zhang and Mitchell, {J. F.} and Botana, {A. S.} and V. Bisogni and Norman, {M. R.} and S. Johnston and Dean, {M. P.M.}",
note = "Funding Information: We thank Kenji Ishii for helpful discussions. Work at Brookhaven National Laboratory (RIXS measurement and interpretation, and cuprate sample synthesis) was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. Work at Argonne was supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division (nickelate sample synthesis and first-principles calculations). A. B. acknowledges support from NSF Grant No. DMR 2045826. S. J. acknowledges support from the U.S. DOE, Office of Science, Office of Basic Energy Sciences, under Award No. DE-SC0022311. X. H. was supported by the Gordon and Betty Moore Foundation{\textquoteright}s EPiQS Initiative through Grant No. GBMF9074. This research used resources at the SIX beamline of the National Synchrotron Light Source II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility at Argonne National Laboratory, and is based on research supported by the U.S. DOE Office of Science-Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Publisher Copyright: {\textcopyright} 2022 authors. Published by the American Physical Society.",
year = "2022",
month = mar,
doi = "10.1103/PhysRevX.12.011055",
language = "English (US)",
volume = "12",
journal = "Physical Review X",
issn = "2160-3308",
publisher = "American Physical Society",
number = "1",
}