Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 49: Poster Nanostructures at Surfaces

O 49.1: Poster

Tuesday, March 18, 2025, 18:00–20:00, P2

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

The deposition and annealing of small amounts of Au on clean Si substrates often lead to enticing nanostructures showing, e. g., spin ordering on vicinal Si(111) substrates or self-doping by adatoms on planar Si(111). A curious case are Au induced nanostructures on Si(110) for which the phase diagram is known in the submonolayer to monolayer regime, but for which few detailed studies exist, although, quasi-1D metallicity has been proposed for one of the nanostructures.

Here, the various nanostructures and their evolution are studied in real space using scanning tunnelling microscopy measured in MAX IVs SPM Support Lab, with core-level and angle-resolved photoemission spectroscopy obtained at the FlexPES beamline of the MAX IV Laboratory. For lowest Au coverages, a 2x1 superstrusture showing a distinct Au 4f core-level component forms. With increasing Au coverage, rows of 2x3 subunits develop leading to the formation of the 2x5 reconstruction with quasi 1D-metallicity and the two-domain (4,0)x(±1,3) high coverage phase, which shows a high stability and recoverability in UHV. This stability is shared with Au silicide nanowires, which grow in the mono- to multilayer Au coverage regime. Since there are no stable bulk Au silicides, the observation of Au silicide nanowires is a beautiful reminder that surfaces and interfaces in general are different and often deviate from bulk expectations.

Keywords: silicon; nanowires; STM; XPS; ARPES