THE DEVELOPMENT OF METALLIC BEHAVIOR IN CLUSTERS ON SURFACES

The transition between metallic and insulating behaviour in three prot otype nanometre scale systems, alkali metal monolayers adsorbed on gra phite, C-60 monolayers adsorbed on metal surfaces and small metal clus ters on surfaces, are examined. The transition between metallic and no n-metallic behaviour is shown to be governed by fundamentally differen t physical phenomena in each system, indicating the need to consider t he precise details of individual systems. The power of the surface sci ence techniques of electron energy loss spectroscopy (EELS) and photoe mission spectroscopy (PES) for investigating metallic and insulating b ehaviour in nm scale systems is demonstrated via measurements made on the model systems. We also review the state-of-the-art in cluster beam deposition and show that it is now possible to create monodisperse su pported cluster films, the electronic structure of which may be interr ogated by EELS and PES.