1. Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
2. Leibniz-Institut für Kristallzüchtung (IKZ), 12489 Berlin, Germany
3. Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
4. Scientific-Practical Materials Research Center of NAS of Belarus, Minsk 220072, Belarus