Nonlocal Interactions in the Double Perovskite Sr<sub>2</sub>FeMoO<sub>6</sub> from Core-Level X-ray Spectroscopy
Dibya Phuyal, Soham Mukherjee, S. K. Panda, Gabriel Man, Konstantin Simonov, Laura Simonelli, Sergei M. Butorin, Håkan Rensmo, Olof Karis
Abstract
The valence electronic structure of the half-metallic double perovskite Sr2FeMoO6 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 Sr2FeMoO6 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.