Nonlocal Interactions in the Double Perovskite Sr₂FeMoO₆ from Core-Level X-ray Spectroscopy

High Resolution Image Download MS PowerPoint Slide The valence electronic structure of the half-metallic double perovskite Sr 2 FeMoO 6 forms from a strongly hybridized band in the spin-down channel of Fe 3d and Mo 4d states that provides metallic conductivity and a gapped spin-up channel. The ground-state description has previously been explored in terms of many-body interactions where local and nonlocal interactions produce states with a combination of a charge-transfer configuration and intersite charge fluctuations. Here, we provide a qualitative understanding on nonlocal effects in Sr 2 FeMoO 6 using a combination of core-level X-ray spectroscopies, specifically X-ray absorption, emission, and photoelectron spectroscopies. Our spectroscopic data indicate intersite Fe 4p–O 2p–Mo 4d interactions to be the origin of these nonlocalized transitions. Close to the Fermi level, this interaction is dominated by Mo 4d–O 2p character. When our data are compared against first-principles electronic structure calculations, we conclude that a full understanding of the nature of these states requires a spin-resolved description of the hybridization functions and that the nonlocal screening occurs predominantly through hybridization in the minority spin channel of the Mo 4d bands.