Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 54: Metallic Nanowires on Semiconductor Surfaces

O 54.3: Poster

Dienstag, 21. März 2017, 18:30–20:30, P1C

Tin nanowires on vicinal Si(111) surfaces — •Monika Jäger, Herbert Pfnür, and Christoph Tegenkamp — Institut für Festkörperphysik, Leibniz Universität Hannover, Germany

Si(111) surfaces covered by 0.3 ML Sn are known to form a √3×√3 reconstruction and reveal a Mott transition upon cooling below 70 K [1]. This system is now confined to a wire like one-dimensional structure using vicinal Si(111) substrates and investigated by means of STM and LEED.
Adsorption of Sn at 900 K gives rise to a refacetting of the Si(557) surface into a local (223) orientation with an average spacing of 1.58 nm similar to the isoelectronic Pb/Si(557) system (e.g. [2]). This change in orientation ist compensated by wider (111) terraces exhibiting a √3×√3 reconstruction. In order to improve the long-ranged ordering, Si(223) surfaces are used additionally as a substrate. On both vicinal surfaces, the (223)-orientated parts consist of 4 2/3 × 0.332 nm wide (111) terraces which show a 0.75 nm periodicity along the terraces. This is consistent with the × 2 features seen in LEED measurements. Furthermore, the electronic structure is probed at different temperatures by STS.
[1] S. Modesti et al., PRL 98, 126401 (2007).
[2] C. Brand et al., Nat. Comm. 6, 8118 (2015).