Affiliation: | (Physikalisches Institut,Universitat Stuttgart,Pfaffenwaldring 57,70550 Stuttgart,Germany;State Key Laboratory for Mesoscopic Physics,School of Physics,Peking University,Beijing 100871,China;Physics Institute II,University of Cologne,50937 Koln,Germany;Physikalisches Institut der Universitat Wurzburg,97074 Wurzburg,Germany;Institute for Topological Insulators,97074 Wurzburg,Germany) |