Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 96: Metallic Nanowires on Semiconductor Surfaces
O 96.7: Talk
Thursday, March 23, 2017, 16:30–16:45, WIL C107
Spin correlations in the Si(553)-Au nanowire system — •Bernd Hafke1, Tim Frigge1, Tobias Witte1, Boris Krenzer1, Julian Aulbach2, Ralph Claessen2, Jörg Schäfer2, and Michael Horn-von Hoegen1 — 1Universität Duisburg-Essen, Lotharstr. 1, 47057 Duisburg — 2Universität Würzburg, Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), 97074 Würzburg
Deposition of 0.5 ML Au on Si(553) at 650 ∘C results in the formation of Au double-strand chains per Si terrace with a twofold periodicity along the wire. These metallic wires are structurally terminated by Si step edge atoms, which exhibit a three-fold periodicity of half-filled dangling bonds of the Si atoms along the steps. Theory predicts an antiferromagnetic spin ordering of every third Si step edge atom [1]. The long-range interaction of the two-fold and three-fold periodicity is investigated by spot-profile analysis in LEED at a sample temperature of 80 K. The strict two-fold periodicity of the Au atoms is not correlated between adjacent wires as concluded from the streak like intensity in LEED. In contrast, the threefold ordering of the Si spins exhibit a clear ordering perpendicular to the Au wires. A modification of the structure model [2] explains the structural correlation between adjacent Si step edge atoms. The resulting frustrated structure indicates the formation of a 2D spin-liquid in this system [2].
[1] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010).
[2] B. Hafke, et al. PRB 94, 161403(R) (2016).