Negative charge-transfer energy in SrFeO3 revisited with hard x-ray photoemission spectroscopy

Abstract

We report hard x-ray photoelectron spectroscopy on SrFeO3 which is one of the classical conducting transition-metal oxides with a noncollinear magnetic structure. The obtained spectra show a detailed charge-transfer (CT) satellite structure, the Fe 2p3/2 main peak exhibits multiplet splitting, and the deterioration signs present in previous reports are absent here, allowing for a better determination of its intrinsic electronic structure. The results are well described by a FeO6 cluster model with a charge-transfer energy of about −1.0 eV, confirming the values obtained in the previous works. The negative CT energy indicates that the electronic configuration of the tetravalent Fe is d5L rather than d4 where L represents an O 2p hole. The small spectral weight observed at the Fermi level indicates the correlated metallic state with localized Fe 3d electrons and mobile O 2p holes which are governed by a large d−d Coulomb interaction and negative CT energy. Published by the American Physical Society 2024