Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 50: Poster: Nanostructures on Surfaces II

O 50.6: Poster

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

Temperature-dependent order-disorder transition in the Si(553)-Au nanowire system — •Bernd Hafke, Tim Frigge, Tobias Witte, Boris Krenzer, and Michael Horn-von Hoegen — Universität Duisburg-Essen, Lotharstr. 1, 47057 Duisburg

Deposition of 0.5 ML Au on Si(553) at 650 ^∘C results in the formation of Au double-strand chains with a twofold periodicity along the terraces of the vicinal Si surface. These metallic wires are structurally terminated by Si step edge atoms, where every third atom exibits a dangling bond leading to a threefold periodicity. Theory predicts magnetic properties of these interacting half-filled Si step edge atoms [1,2]. The long-range interaction of the twofold and threefold periodicity is investigated by spot-profile analysis in LEED at sample temperatures between 60 K and 180 K. The correlation length of Si step edge atoms along and perpendicular to the steps abruptly decreases upon heating above a temperature of T≈100 K, respectively. Interestingly, the streak-like intensity, indicative for the twofold periodicity of the Au atoms, shows an opposite behavior, i.e., an increase in correlation lenth upon heating. These findings are explained within a scenario of an order-disorder transition accompanied with the creation of so-called heavy and light zerodimensional domain boundaries.

[1] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010).

[2] B. Hafke, et al. PRB 94, 161403(R) (2016).