Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Poster Monday: Nanostructures

O 18.1: Poster

Montag, 1. April 2019, 17:45–20:00, Poster F

Theoretical investigation of H adsorption at the Si(557)-Au surface — •Ferdinand Ziese, Kirs Holtgrewe, Christof Dues, and Simone Sanna — Justus-Liebig-Universität Giessen, Institut für Theoretische Physik Heinrich-Buff-Ring 16, 35392 Gießen, Germany

Vicinal Si(111)-Au surfaces feature single or double atomic Au chains on each terrace of the stepped Si surface [1]. The metallic wires are electronically decoupled from the substrate and represent quasi 1D nanoobjects. In order to tune the wire metallicity, different atoms and molecules can be adsorbed on the system [2]. In this work, we investigate the adsorption atomic hydrogen at the Si(557)-Au surface within density functional theory. In a first step, the favorable adsorption site is determined as a function of the H coverage by means of potential energy surface calculations. While H adsorbs on the Si step edge on pristine surfaces, the favored site for the secondary H adsorption is on top of the so-called rest atom. Band structure calculations reveal that H acts as an electron donor, influencing the electronic states related to the adsorption sites. For an H coverage corresponding to two H atoms per (5x2) surface unit cell, we predict the formation of an electronic band gap at the Fermi energy and a metal-to-insulator transition.

[1] N. J. Crain et al., Phys. Rev. B 69, 125401 (2004)

[2] Z. Mamyev et al., Phys. Rev. Mat. 2, 066002 (2018)