Resonant photoemission and spin polarization of Co_1-xFe _xS₂

The valence band occupied state electronic structure of Co1-xFexS2 in the region of the Fe/Co 3d bands has been investigated using photoemission and spin-polarized photoemission. As measured by using spin-polarized ultraviolet photoemission, the surface Fermi level spin polarization of Co1-xFexS2 thin films at 50 K, specifically at x = 0, 0.05, 0.10 and 0.15, was found to be much reduced compared to that of the bulk. The spin polarization nonetheless increases with Fe concentration. The resonant photoemission spectroscopy provides evidence that S bands have a strong resonance at the photon energy corresponding to the Co 2p core level, indicating strong hybridization between Co and S bands in Co1-xFexS2 (at small x). Similar evidence exists for Fe hybridization with the S bands.