Contest between surface resonances and surface states at 3d ferromagnets

The surface electronic structure of band ferromagnets in the vicinity of the Fermi level is strongly influenced by the magnetic d bands. A comparative study of the closed-packed surfaces of Ni, Co, and Fe shows that surface resonances dominate over surface states with increasing d-band influence. Our theoretical analysis distinguishes between surface states and resonances thereby providing a systematics of surface-related spectral features at ferromagnets. This solves the long-standing surface-state puzzle in the literature of sometimes contradicting (inverse) photoemission results.