Affiliation: | 1. 1. Physikalisches Institut, Universit?t Stuttgart, Stuttgart, Germany;2. Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia;3. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia;4. Max Planck Institut für Festk?rperforschung, Stuttgart, Germany;5. Institute de Physique de la Matière Condensée, Ecole Polytechnique de Lausanne, Lausanne, Switzerland |