1. Institute of Physics, National Academy of Sciences of Ukraine, 46, Prospekt Nauky, 03028 Kyiv, Ukraine
2. Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, 14-b Metrolohichna str., 03680 Kyiv, Ukraine
3. Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, 3, Krjijanovskogo, 03142 Kyiv, Ukraine
4. Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, USA
5. Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA