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O: Fachverband Oberflächenphysik

O 46: Poster Session IV: Semiconductor substrates II

O 46.5: Poster

Tuesday, March 2, 2021, 13:30–15:30, P

Au silicide nanowires on Si(110) — •Stephan Appelfeller — MAX IV Laboratory, Lund University, Sweden

The Au-Si phase diagram is of simple eutectic nature without any stable bulk Au silicide. Nevertheless, metastable Au silicide structures have been observed at Au-Si interfaces and on surfaces. Especially, Au atomic chains on planar and vicinal Si(111) surfaces were investigated in recent years since they showed very enticing properties, e.g., self-doping by adatoms, 1D metallic behavior, or spin chain formation.

Here, Au induced nanostructures on the Si(110) surface are studied using LEED, STM and STS, and core-level and valence band PES. Due to the symmetry of the substrate, single-domain Au reconstructions form, e.g., a 2 × 5 superstructure known to show a 1D metallic band structure, which show interesting adatom structures. However, the focus of this study is on Au silicide nanowires. Their diffraction data are not characterized by well-defined spots, but by streaky features. While the dimensions of the nanowires are directly obtainable in STM, they only show a structurless appearance for widely varying tunneling conditions. Nevertheless, structural information is available by tuning the surface sensitivity in PES indicating silicide formation. Both PES and STS experiments show a finite density of states at the Fermi level for the nanowires suggesting (semi-)metallic behaviour.