Bulk and Surface Plasmons in Artificially Structured Materials

The bulk and surface collective charge density excitations of metallic and semiconducting superlattice structures are studied. Because of the new periodicity along the axis of an infinite superlattice, these plasma modes form bands which satisfy Bloch's theorem. The dependence of the band structure on the material parameters is investigated. For finite or semi-infinite systems novel surface plasmons can occur. The coupling of the bulk and surface collective modes to external probes is reviewed.