1. Physikalisches Institut; Experimentelle Physik II; Universität Würzburg; 97074 Würzburg Germany
2. V. S. Sobolev Institute of Geology and Mineralogy; Siberian Branch; Russian Academy of Sciences; 630090 Novosibirsk Russia
3. Novosibirsk State University; 630090 Novosibirsk Russia
4. A. V. Rzanov Institute of Semiconductor Physics; Siberian Branch; Russian Academy of Sciences; 630090 Novosibirsk Russia
5. Wilhelm Conrad Röntgen-Center for Complex Material Systems (RCCM); Universität Würzburg; 97074 Würzburg Germany