A study of the electronic structure of FeSe1-xTex chalcogenides by Fe and Se K-edge x-ray absorption near edge structure measurements

Fe K-edge and Se K-edge x-ray absorption near edge structure (XANES) measurements are used to study the FeSe1-xTex electronic structure of chalcogenides. An intense Fe K-edge pre-edge peak due to Fe 1s → 3d (and admixed Se/Te p states) is observed, showing substantial change with Te substitution and x-ray polarization. The main white line peak in the Se K-edge XANES due to Se 1s→4p transition appears similar to the one expected for Se2- systems and changes with Te substitution. Polarization dependence reveals that unoccupied Se orbitals near the Fermi level have predominant px,y character. The results provide key information on the hybridization of Fe 3d and chalcogen p states in the Fe-based chalcogenide superconductors.