1. Institute of Solid State Physics, RAS, Chernogolovka 142432, Russia
2. Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
3. Laboratory for Condensed Matter Physics, National Research University Higher School of Economics, Moscow 101000, Russia
4. Solid State Physics Laboratory, ETH Zurich, Otto-Stern-Weg 1, 8093 Zurich, Switzerland