D.A. Usanov - Dr.Sc. (Phys.-Math.), Professor, Head of the Department "Solid State Physics", Saratov State University named after N.G. Chernyshevskii. E mail: UsanovDA@info.sgu.ru
S.A. Nikitov - Corresponding Member RAS, Dr.Sc. (Phys.-Math.), Professor, Deputy Director, Institute of Radio-engineering and Electronics of RAS named after V.A. Kotelnikov. E-mail: nikitov@cplire.ru
A.V. Skripal - Dr.Sc. (Phys.-Math.), Professor, Department "Solid State Physics", Saratov State University named after N.G. Chernyshevsky. E-mail: skripala_v@info.sgu.ru
A.P. Frolov - Researcher, Department "Solid State Physics", Saratov State University named after N.G. Chernyshevsky. E-mail: tanto_85@mail.ru