SKM 2021 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 4: Poster
DS 4.25: Poster
Dienstag, 28. September 2021, 10:00–13:00, P
Surface-localized phonon modes on the Si(553)-Au surface — •Julian Plaickner1,2, Eugen Speiser1, Sandhya Chandola1,2, Christian Braun3, Wolf Gero Schmidt3, Norbert Esser2,4, and Simone Sanna5 — 1Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn Meitner Platz 1, 14109 Berlin — 2Leibniz-Institut für Analytische Wissenschaften, ISAS e.V., Schwarzschildstraße 8, 12489 Berlin — 3Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, 33095 Paderborn — 4Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin — 5Institut für Theoretische Physik and Center for Materials Research (LaMa), Justus Liebig Universität Gießen, Heinrich Buff Ring 16, 35392 Gießen
The Si(553)-Au surface is investigated with Raman spectroscopy and ab-initio calculations. A characterization of the phonon modes is provided below and above the phase transition temperature (Phys. Rev. B 103, 115441 (2021)). Some phonon modes shows a significant temperature dependence. The analysis of the calculated displacement patterns indicates that these modes are localized at the Si step edge or involve a change of the Au-Au bond length. The large temperature-induced frequency shift observed for transversal Au-related modes demonstrates that the dimerization is significantly affected by the phase transition due to charge transfer between Au- and Si-related states. The charge transfer leads to Raman scattering by charge density fluctuations, which is responsible for the detected Raman activity even for such modes that should be silent due to symmetry.