Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Methods: Atomic and Electronic Structure II
O 52.1: Vortrag
Donnerstag, 29. März 2007, 11:15–11:30, H42
Electronic excitations and excited-state forces of the H:Si(001)-(2x1) monohydride surface — Neng-Ping Wang1, •Michael Rohlfing2, Peter Krüger3, and Johannes Pollmann3 — 1Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg — 2Fachbereich Physik, Universität Osnabrück — 3Institut für Festkörpertheorie, Universität Münster
We investigate electronic excitations of the H:Si(001)-(2×1) monohydride surface using first principles approaches. Density-functional theory is used to calculate the ground state geometry of the system. The quasiparticle band structure is calculated within the GW approximation. Taking the electron-hole interaction into account, electron-hole pair states and optical excitations are obtained from the solution of the Bethe-Salpeter equation for the electron-hole two particle Green function. In this work we focus, in particular, on localized excitations of the silicon-hydrogen bonds at the surface layer. These excitations give rise to an outward-directed force on the hydrogen atoms, which may well explain their optically induced desorption from the surface as observed inrecent experiments. The localization of the excitation is described by an artificial confinement potential in addition to standard many-body perturbation theory.
[1] N.-P. Wang, M. Rohlfing, P. Krüger, and J. Pollmann, Phys. Rev. B 74, 155405 (2006).