First-principles study of benzene adsorption on the SiC(001)-(3×2) surface

Adsorption of benzene on the SiC(001)-(3×2) surface is investigated employing density-functional theory within the generalized gradient approximation. Due to the relatively large Si dimer distance on the clean surface, benzene appears to adsorb only in a standard-butterfly configuration on single dimers. Such a well-defined structure might turn out to be of particular interest for fundamental experimental investigations as well as for surface functionalization by organic molecules. The reaction pathway of benzene from an initial state in vacuum to the final adsorption state in the standard-butterfly configuration on the surface is explored and the reaction process is analyzed employing maximally localized Wannier functions. The electronic structure of the optimized adsorption configuration is discussed in terms of the surface-band structure, charge and state densities, as well as scanning tunneling microscopy images.