Spin-polarized photoemission studies of the adsorption of O and S on Fe(001)

Spin-resolved angle-resolved photoemission spectra have been measured for the adsorption systems Fe(001)-p(1×1)O and Fe(001)-c(2×2)S. Adsorbate-induced features in the spectra display exchange splittings (ΔE) and linewidths which vary with ${\mathit{k}}_{\mathrm{?}}$, with orbital symmetry (${\mathit{p}}_{\mathit{x}}$ or ${\mathit{p}}_{\mathit{z}}$), and with spin character. For adsorbate ${\mathit{p}}_{\mathit{z}}$ orbitals, the measured ΔE is larger at the center of the surface Brillouin zone (1.3 eV for O, 0.5 eV for S) than at the zone boundary (0.25 and 0.2 eV, respectively). The results are compared with the predictions of tight-binding simulations and first-principles calculations.