1. Institute of Theoretical Physics, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
2. Center for Materials Research (ZfM), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen 35392, Germany
3. CNRS/Aix-Marseille Université, Centre Interdisciplinaire de Nanoscience de Marseille, UMR 7325, Campus de Luminy, Marseille 13288 Cedex 9, France
4. Institute of Experimental Physics I, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany
5. Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, Giessen 35392, Germany