1. Institute for Physics of Microstructures RAS, Afonino, Nizhny Novgorod 603087, Russia
2. Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Lavrentiev Ave, 13, Novosibirsk, 630090 Russia
3. Faculty of Physics, Novosibirsk State University, Pirogova Street, 2, Novosobirsk, 630090 Russia
4. Faculty of Radiophysics, Lobachevsky State University, Nizhny Novgorod 603950, Russia
5. Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany