Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 95: Semiconductor Substrates: Metallic Nanowires

O 95.4: Vortrag

Freitag, 5. April 2019, 11:15–11:30, H14

1D- plasmons and their H-induced modification on the Si(557)-Au surface — •Zamin Mamiyev¹, Simone Sanna², Christoph Tegenkamp¹, and Herbert Pfnür¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover, Hannover, Germany — ²Theoretische Physik, Justus-Liebig-Universität Gießen, Gießen

Recently significant progress has been made on metallic atomic wires on the stepped Si surfaces. However, there are still fundamental questions concerning substrate wire interaction, tunability in atomic scale et.c. need to be clarified. Such wires host anisotropic plasmonic excitations which contain significant information about excitated states and also have a potential application in nano-optoelectronics. Here we use plasmon spectroscopy and atomistic DFT calculations to study the H-induced modifications of quasi-1D plasmons in Au atomic wires on the Si(557) surface. Single atomic Au chains per terrace form upon evaporation of 0.19ML Au onto this surface while emerging other structural motifs with an individual chemical potential. Adsorption of atomic H induces a reduction of dispersion and levelling of the dispersion around 0.45 eV for k_∥> 0.08 Å, indicative of band gap opening in the unoccupied part of the band structure. No extrapolation to E=0 at k_∥= 0 is possible any more, indicating increased electronic localization and/or influences by disorder. These findings are corroborated by DFT calculations, which predict adsorption of H first on the Si step edge and then on the Si rest atom row. Using the relation between e-h continuum and plasmon dispersion, the modification of band structure and its consequences on plasmonic excitation will be discussed.