Magnetic exchange splitting and band dispersion of surface states on Fe(100)

We have determined the band dispersion and magnetic exchange splitting of odd-symmetry Shockley surface states along the $\overline{\Delta }$ and $\overline{\Sigma }$ lines in the surface Brillouin zone of Fe(100) using angle-resolved photoemission. The average surface exchange splitting along the $\overline{\Delta }$ and $\overline{\Sigma }$ lines is larger than the average bulk value. Surface-state band dispersion and binding energies along $\overline{\Sigma }$ are in good agreement with recent slab calculations.