Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.73: Poster

Donnerstag, 19. März 2015, 09:30–12:00, Poster A

Atomically resolved Pb structures on vicinal Si(557) — •Monika Jäger, Christian Brand, Herbert Pfnür, and Christoph Tegenkamp — Institut für Festkörperphysik, Leibniz Universität Hannover, Germany

Vicinal Si(557) surfaces covered by 1.31 ML Pb reveal a 1D transport behavior below 78 K [1]. Furthermore, recent spin resolved ARPES measurements have shown that the insulating behavior across the direction of the wires is associated with the formation of a spin-orbit density wave [2]. In order to correlate these findings with the morphology the atomic structure was investigated by means of STM. Adsorption of Pb at 600 K gives rise to a refacetting of the Si surface into a local (223) orientation with an average spacing of 1.58 nm. High resolution STM images have clearly identified √3×√3 reconstructions on the 4 2/3 × 0.332 nm wide (111) terraces. Furthermore, the step edges remain uncovered and reveal the periodicity of the Si-dimers. In addition, the 0.665 nm periodicity along the terraces is superimposed by an additional intensity modulation which is compatible with a 10-fold periodicity deduced from the spot-splitting seen in former high resolution LEED measurements. Phase shifts along the quasi-atomically resolved structures are reminiscent of domain wall structures with √7×√3-symmetry. Our findings show strong similarities with a recent high resolution STM and DFT study for Pb/Si(553) [3].
[1] C. Tegenkamp et.al. PRL 95, 176804 (2005).
[2] C. Tegenkamp et.al. PRL 109, 266401 (2012).
[3] M. Kopciuszy ński et.al. PRB 88, 155431 (2013).