[1] Slovak Acad Sci, Ctr Adv Mat Applicat CEMEA, Dubravska Cesta 5807-9, Bratislava 84511, Slovakia
[2] Natl Res Univ, Moscow Inst Phys & Technol, Phystech Sch Biol & Med Phys, 9 Inst Skiy Per, Dolgoprudnyi 141701, Russia
[3] Vienna Univ Technol, Inst Mat Chem, Getreidemarkt 9-BC-2, A-1060 Vienna, Austria
[4] Univ Vienna, Fac Phys, Strudlhofgasse 4, A-1090 Vienna, Austria
[5] Russian Quantum Ctr, 30 Bolshoy Bulvar, Skolkovo Innovation City 121205, Moscow, Russia
[6] Natl Res Univ, Moscow Inst Phys & Technol, Ctr Photon & 2D Mat, 9 Inst Skiy Per, Dolgoprudnyi 141701, Russia