Electronic properties of FeSe1−xTex probed by x-ray emission and absorption spectroscopy

The electronic structure of FeSe1-xTex chalcogenide superconductors has been studied by x-ray emission (XES) and x-ray absorption (XAS) as a function of Te substitution. The Fe K beta XES spectra reveal a relatively low spin state for Fe in FeSe1-xTex 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 FeSe1-xTex chalcogenides