Local Variation of surface properties
Spatially resolved measurement of the electronic structure and the vibrational properties of structured surfaces demonstrated substantial changes of these properties in dependence of local environment. For instance, the intersection of a bulk dislocation with the surface changes the electronic structure of the surface state on Ag(111). The onset of this surface state also varies with terrace width to an extent that it is even depopulated for terraces smaller than 3.2 nm. These changes influence the adsorbate-surface interaction. We have shown already that growth and stability of metallic nanostructures depend crucially on the electronic structure of the terrace. These studies will be extended to reactivity studies.
Only our group has so far been successful in imaging the phonon structure of a surface with inelastic scanning tunneling microscopy. This study showed that the phonon spectrum varies locally on different parts of the reconstructed Au(111) surface.
We plan to investigate the influence of defects onto the local phonon structure. Because of the low intensity of the phonon signal this is a technically challenging project. It will give unprecedented insight into the local phonon structure.
