Localization of optically excited states by self-trapping.
We discuss the localization of the surface exciton at the Si(111)- (2x1) surface due to self-trapping, which leads to a characteristic temperature-dependent linewidth of the optical response and to a significant Stokes shift of the luminescence. Self-trapping results in this case from a structural relaxation in the excited state, caused by the interplay between electronic and geometric degrees of freedom. The most significant contribution to this effect comes from one single geometric deformation mode which is driven by the internal electronic charge transfer in the self-trapped exciton.
Rohlfing
Michael
M
Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany.
Pollmann
Johannes
J