INTERACTION OF C-60 WITH THE AU(111) 23X-ROOT-3 RECONSTRUCTION

The interaction of C60 with the 23 X square-root 3 Au(111) reconstruction was studied using UHV scanning tunneling microscopy (STM). Preferred adsorption at fcc or bulk terminated sites was observed on deposition and after annealing to partially desorb the C60 layer. Disruptions in the reconstruction were observed on the bare Au substrate neighboring the C60 layer with reconstruction ridges terminating at the layer edges rather than continuing through the adsorbed layer. When low C60 deposition rates were used, STM measurements indicated that virtually all Au atoms at the C60 interface occupy fcc bulk terminated sites indicating that C60, unlike ordinary hydrocarbons, interacts strongly enough with Au to lift the reconstruction. These results are contrasted with results obtained at much higher deposition rates that showed an altered reconstruction at the C60-Au(111) interface. This variation with deposition rate is attributed to the concerted motion of Au atoms required to lift the reconstruction creating a kinetic constraint.