Electronic and atomic structures of a Sn induced 3√3x3√3 superstructure on the Ag/Ge(111) √3x√3 surface

We have investigated sub-monolayer coverages of Sn on the Ag/Ge(111) surface. It was found that ≈0.45 monolayer (ML) resulted in a new, well-defined, reconstruction with a periodicity. The periodic structure of the surface atoms was verified by low energy electron diffraction and scanning tunneling microscopy. The electronic structure was studied in detail using angle resolved photoelectron spectroscopy and core level spectroscopy at a temperature of 100 K. Several surface bands were identified and their dispersions are presented along the –– and –– high symmetry lines of the surface Brillouin zone (SBZ). The surface has a metallic character since there is a strong surface band crossing the Fermi level near -points coinciding with -points of the 1×1 SBZ. The Fermi contour of the metallic band showed a hexagonal shape in contrast to the circular shaped Fermi contour of the initial surface. Both empty and filled state STM images showed a hexagonal arrangement of protrusions which show a local periodicity and a superimposed modulation of the apparent heights with a periodicity.Vid tiden för disputation förelåg publikationen endast som manuskript