Quantum well and quantum wire states at metal surfaces

Novel effects in magnetic multilayer structures, such as oscillatory magnetic coupling and "giant" magnetoresistance, have created new materials that allow for an order of magnitude higher sensitivity in the detection of magnetically-recorded data. Determination of their electronic and magnetic structures with angle-resolved photoemission and inverse photoemission reveals quantized states in the noble metal spacer layers which are connected with oscillatory magnetic coupling and have implications on magnetoresistance. These states can be understood by a simple interferometer model, including the spin-dependent interface reflectivity that polarizes them and transmits the magnetic coupling through the noble metal spacer.Current efforts are discussed, which aim towards fabricating quantum wires and lateral superlattices on metals by decorating steps at vicinal surfaces. STM work on the growth mode of such structures is presented, which uses spectroscopic contrast to distinguish different metals. Specific electronic states at decorated step edges are found with inverse photoemission.