Adsorption and electronic structure of single C 60F 18 molecule on Si(1 1 1)-7 × 7 surface

• Published in: Chemical physics letters Vol. 482; no. 4; pp. 307 - 311
• Main Authors: Bakhtizin, R.Z., Oreshkin, A.I., Murugan, P., Kumar, Vijay, Sadowski, J.T., Fujikawa, Y., Kawazoe, Y., Sakurai, T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2009
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2009.10.020

Isosurface of charge densities difference (Δ ρ) between C 60F 18 adsorbed on a Si(1 1 1)-7 × 7 surface and non-interacting Si(1 1 1)-7 × 7 surface plus the C 60F 18 molecule with the same atomic positions as in the case of the adsorbed system, shows the surface dipole induced by the molecule. Large Δ ρ on Si surface are regions where A-type of F atoms interact with the surface, while small Δ ρ occurs where B-type of F atoms interact with the surface. Spatially resolved images of an individual C 60F 18 molecule on Si(1 1 1)-7 × 7 surface obtained from STM and ab initio calculations show that the fluorofullerene molecules interact with the Si(1 1 1) surface with F atoms pointing down towards the surface. A large electric dipole moment of the molecule induces strong polarization on the surface but the charge transfer is small. Comparison between the experimental and calculated images indicates that during the time of image collection, some of the F atoms move to the surface due to F binding energy on a Si surface being nearly twice of the mean value on the C 60 molecule.