Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Nanostructures at Surfaces: 1D and 2D Structures and Networks
O 51.13: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1C
Vibrational Eigenmodes of the Au-(√3×√3)/Si(111) surface reconstruction examined by Raman spectroscopy and first-principles calculations — •Benedikt Halbig1, Martin Liebhaber1, Utz Bass1, Jean Geurts1, Eugen Speiser2, Jochen Räthel2, Sandhya Chandola2, Norbert Esser2, Sergej Neufeld3, Marvin Krenz3, Simone Sanna3, and Wolf Gero Schmidt3 — 1Uni. Würzburg, Exp. Physik III, Würzburg, Germany — 2Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Berlin, Germany — 3Uni. Paderborn, Dep. Physik, Paderborn, Germany
Submonolayer coverages of metal adatoms on semiconductor surfaces show particular reconstructions, e.g., (5×2) and (√3×√3) for the Au/Si(111) system. Raman spectroscopy proves to be a sensitive probe analysing vibration eigenmodes of these material systems, as demonstrated for Au-(5×2)/Si(111) [1]. We report on the investigation of Au-(√3×√3)R30∘/Si(111) by polarized in situ Raman spectroscopy in combination with first-principle calculations within Density Functional Theory. The Raman spectra, taken at 300 K and ≈ 20 K, reveal a main peak at 73 cm−1 accompanied by adjacent peaks on the low-energy side, a singular peak at 30 cm−1, and a group of three peaks around 115 cm−1. Density Functional Theory Frozen-Phonon calculations were carried out for three structural models labeled twisted-trimer, conjugate honeycomb-chained-trimer and honeycomb-chained-trimer [2]. [1] M. Liebhaber et al., PRB, accepted (2016). [2] J. Y. Lee et al., JKPS, 55, 6 (2009), and references therein.