Spin-polarized and spin-integrated photoemission study of itinerant ferrimagnetic iron chalcogenides

Itinerant ferrimagnetic metals Fe₇S₈ and Fe₇Se₈ and antiferromagnetic semiconductor FeS have been studied by spin-polarized and spin-integrated photoemission and inverse-photoemission spectroscopy. Comparison with the density of states given by band-structure calculations indicates that the Fe 3d band is narrowed with spectral weight transfer towards higher binding energies and that the intensity at the Fermi level is suppressed. The band narrowing and the spectral weight transfer is reproduced by including the self-energy correction, suggesting the importance of electron correlation. Spin-polarized photoemission spectra of Fe₇S₈ and Fe₇Se₈ show negative spin-polarization near the Fermi level and spin-dependent correlation effect.