Affiliation: | National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China; 2 Beijing Key Laboratory of Nano-Photonics and Nano-Structure(NPNS),Department of Physics,Capital Normal University,Beijing 100048, China; 3 Information Awareness and Confrontation,Beijing Institute of Technology,Beijing 100081,China; 4 Division of Solid State Physics,Lund University,Lund 22100,Sweden |