Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 40: Metallic nanowires on the atomic scale (joint session with O)
DS 40.10: Talk
Friday, March 20, 2015, 12:15–12:30, H 2032
Vibrational properties of Au nanowires on Si(553) and Si(111) surfaces — •Sergej Neufeld1, Simone Sanna1, Jochen Räthel2, Norbert Esser2, and Wolf-Gero Schmidt1 — 1Lehrstuhl für Theoretische Physik, Universität Paderborn — 2Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Berlin
Metallic nanowires on semiconducting substrates such as silicon and germanium have been attracting considerable interest in the last decade. Besides various potential applications as non ohmic conductors, they are candidate systems for the demonstration of the basic concepts of one-dimensional physics such as electron correlation and Luttinger liquid behavior. In particular, the phase transitions observed on these systems have been controversially discussed and are still poorly understood. 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 well-established microscopic structural models of Au nanowires on various Si surfaces based on density functional theory are available in the literature, few is known about their vibrational properties. In this work, the phonon eigenmodes and eigenfrequencies of the Au/Si(553) and Au/Si(111) wires are calculated from first-principles at the center of the Brillouin zone. Several surface localized phonon modes are found, whose phonon frequencies can be directly compared with the spectra obtained by Raman measurements. Raman scattering efficiences are calculated in order to facilitate the comparison between experiment and theory.