Magnetic interlayer coupling and interaction between interface states in aquantum-well system

A first-principles Green's function technique has been used to investigate the magnetic interlayer coupling and the electronic structure responsible f or the magnetic interaction in a bcc Fe/Cu-N/Fe system. We discuss the clos e relation between the interlayer coupling, the bulk Fermi surface of the s pacer material, and the dispersion of the quantum-well states in the two-di mensional Brillouin zone, As a function of spacer thickness, we find an osc illatory long-range energy splitting of Fe/Cu interface states which is sho wn to be an example of a long-range oscillatory interface interaction trans mitted by the spin-polarized quantum-well states of the Cu spacer. These in teracting interface states may provide a signature of the magnetic coupling in multilayers.