Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 50: Poster: Nanostructures on Surfaces II

O 50.5: Poster

Dienstag, 13. März 2018, 18:15–20:30, Poster B

Gold-induced Surfaces on Stepped Germanium: Towards Atomic Models — •Tim Wagner, Julian Aulbach, Ralph Claessen, and Jörg Schäfer — Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg

Self-assembly of gold atoms on terraced Si(hhk) or Ge(hhk) substrates stabilizes certain surface orientations. While Si(553)-Au and Si(557)-Au have already been thoroughly examined, showing honeycomb step edges with regular arrays of spins, the atomic structure of the related Ge(hhk)-Au systems has not yet been determined. In order to investigate the influence of the substrate on the atomic structure, we perform scanning tunneling microscopy and low energy electron diffraction measurements on Ge(hhk)-Au surfaces. Based on our results, we propose first atomic structure models for Ge(221)-Au, Ge(335)-Au and Ge(557)-Au taking into account the known structural motifs of the Si(hhk)-Au family [1] and of the metal-induced Ge(111)-M systems [2]. While the Ge(335)-Au and Ge(557)-Au surface reconstructions display a great resemblance to their Si(hhk)-Au counterparts, in the special case of Ge(221)-Au the missing registry shift between neighboring step edges imposes an unusual rectangular unit cell, giving rise to a potentially different kind of inter-step correlation.

[1] J. Aulbach et al., Nano Lett. 16(2698) (2016).

[2] A. Tomaszewska et al., Ultramicroscopy 111(392) (2011).