ELECTRONIC BAND-STRUCTURE AND PHOTOEMISSION SPECTRA OF FE7S8

First-principles electronic band structure calculations are performed for a cation-deficient NiAs-type ferrimagnet Fe7S8 (pyrrhotite) by usi ng the linearized augmented-plane-wave (LAPW) method based on the loca l density approximation for the exchange-correlation potential. The ma gnetic moment, the magnetic hyperfine field, the isomer shift, and the Fe 3s core-level spin-splitting are evaluated for each iron-site. Val ence-band ultraviolet photoemission and inverse photoemission spectra are calculated for the ferrimagnetic state of Fe7S8 and the results ar e compared with recent observations.