THEORY OF IMAGE STATES AT MAGNETIC-SURFACES

The interaction of the spin of an electron in an image state with surf ace magnetism produces a spin-splitting which can be probed experiment ally, most directly using spin-polarised inverse photoemission. There has been some debate about whether the spin-splitting is due to the sp in-dependence of the surface potential barrier, or to the spin-depende nce of the scattering of the surface state by the crystal potential. W e have shown that in the case of image states at Fe(110) both effects contribute, but with opposite sign: the major effect is the effect of the crystal, and the potential barrier which has the opposite spin-pol arization reduces the spin-splitting. A splitting of 55 meV is found f or the n = 1 state, which has been confirmed by experiment. The disper sion of the spin-split states is discussed, particularly their interac tion with the spin-split continua which produces different surface res onance behaviour for the two spins.