Localization of substrate-induced modification in the electronic structure of C60 at fullerene-metal interfaces

Photoemission and electron-energy-loss-spectroscopy studies of C60 films deposited on Au~110! demonstrate that only the first layer of molecules, directly in contact with the metal substrate, display significant changes in electronic structure. If the Au~110! surface is precovered with Cs it is found that, at 298 K, the Cs can diffuse readily into a C60 thin film, preventing the formation of a localized interface. However, if a Cs precovered Au~110! sample is held at 98 K, subsequent deposition of C60 results in the formation of a spatially localized interface with only the closest two fullerene layers to the original metal surface modified by charge transfer.