Electronic properties of FeSe _1xTe _x probed by x-ray emission and absorption spectroscopy

The electronic structure of FeSe _1xTe _x chalcogenide superconductors has been studied by x-ray emission (XES) and x-ray absorption (XAS) as a function of Te substitution. The Fe Kβ XES spectra reveal a relatively low spin state for Fe in FeSe _1xTe _x superconductors, persisting in the whole range of Te substitution. The Fe K-edge high-resolution XAS shows systematic spectral changes due to the evolving hybridization between the Fe 3d (4p) and chalcogen p (d) orbitals. The resonant inelastic x-ray scattering (RIXS) spectra hardly show any feature except the one due to charge transfer from occupied to unoccupied bands, that changes substantially from FeSe to FeTe. The results provide important information on the electronic states and their evolution in the FeSe _1xTe _x chalcogenides.