1. Centre for Innovation Competence SiLi-nano, Martin-Luther-University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Strasse 3, 06120 Halle (Saale), Germany
2. Interdisciplinary center of material science, Martin-Luther-University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, 06120 Halle (Saale), Germany
3. Institute of Physics, Martin-Luther-University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany
4. Institute for Physics of Microstructures of the Russian Academy of Sciences, Academicheskaya Str. 7, Nizhny Novgorod 603950, Russia
5. Lobachevsky University, Gagarin av. 23, Nizhny Novgorod 603950, Russia
6. Department of Physics and Engineering, ITMO University, St. Petersburg 197101, Russia