Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Metallic Nanowires on Semiconductor Surfaces

O 18.5: Poster

Montag, 7. März 2016, 17:00–19:30, Poster A

Au/Si(553) and Au/Si(111) surface phonons and Raman scattering efficiencies calculated from first principles — •Sergej Neufeld, Simone Sanna, and Wolf Gero Schmidt — Theoretische Physik, Universität Paderborn

Metallic nanowires on semiconducting substrates have been attracting considerable interest in the last decades. Self organizing gold chains at vicinal surfaces such as the Si(553) and Si(111) are of particular interest, as the use of stepped templates allows to vary the geometric parameters and, thus, tune the inter-chain coupling. While microscopic structural models of Au nanowires on various Si surfaces are available in the literature, little is known about their vibrational properties in terms of surface localized phonon mode frequencies, eigenmodes and Raman scattering efficiencies. In this work, the phonon mode characteristics of the Au/Si(553) and Au/Si(111) surfaces are calculated from first-principles. Several surface localized phonon modes are found, whose phonon frequencies can be directly compared with the spectra obtained by Raman measurements. Additionally, the differential Raman cross section of the Au/Si(111) surface is calculated via linear response routines. A qualitative agreement between theoretical and experimental spectra could be observed.