1. Moscow
Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700, Russia
2. Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299, United States
3. École Polytechnique
Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
4. A.V. Shubnikov
Institute of Crystallography, Leninsky
pr. 59, Moscow 119333, Russia
5. NRNU “Moscow Engineering Physics Institute”, Moscow 115409, Russia