Synchrotron-radiation photoemission and x-ray absorption of Fe silicides

The valence-band and core-electron states of the iron silicides FeSi, α-${\mathrm{FeSi}}_2$, and β-${\mathrm{FeSi}}_2$, were measured by synchrotron-radiation photoemission and x-ray absorption. The analysis of the Fe 3s, Fe 3p, and Si 2p core-level photoemission line shape is made by comparing the silicide data with the data for bcc Fe, hcp Co, fcc Cu, ${\mathrm{CoSi}}_2$, and Si(111)7×7 surfaces. The Fe 3p spin-orbit splitting in silicides is resolved spectroscopically. The results are discussed in connection with the electronic properties of the silicides and also provide reference standards for the very active spectroscopic research on the metastable interface-silicide phases of iron.