The C60/Au(III) interface at room temperature : A scanning tunnelling microscopy study

The interface between adsorbed C60 molecules and the (111) surface of gold at room temperature has been studied with the scanning tunnelling microscopy (STM). The first monolayer of C60 on Au(111) is known to exist in several phases: in phase, , and R14 deg , depending on the direction of the close-packed C60 molecules in relation to the close-packing direction of the gold atoms. For the in-phase C60 overlayer where the close-packing direction of the C60 molecules is aligned with that of the gold atoms, we find that the reconstruction of the underlying Au(111) surface remains largely unchanged. For the phase, the surface reconstruction is also preserved to a great extent if the molecular layer sits on a region consisting of small domains. On a larger domain, the structure is found to lift the surface reconstruction of Au(111). The R14 deg structure is observed for the first time in STM and a structural model consistent with findings from both STM and LEED is presented. A fairly regular pattern of atomic re-arrangement with a quasi-period of 6nm is found in regions of the Au(111) surface underneath the R14 deg C60 layer.