1. Research Institute of Physics, Southern Federal University, 194 Stachki Avenue, Rostov-on-Don 344090, Russia
2. Department of Physical Electronics, Chechen State University, Grozny 364015, Chechen Republic, Russia
3. H. I. Amirkhanov Institute of Physics of Daghestanian, Scientific Center of the Russian Academy of Sciences, Makhachkala, Russia