1. Rzhanov Institute of Semiconductor Physics, Novosibirsk 630090, Russian Federation
2. Novosibirsk State University, Novosibirsk 630090, Russian Federation
3. Institute of Strength Physics and Materials Science, 634021 Tomsk, Russian Federation
4. Tomsk State University, 634050 Tomsk, Russian Federation
5. Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique - CNRS, 91128 Palaiseau Cedex, France
6. Boreskov Institute of Catalysis, Novosibirsk 630090, Russian Federation