State Key Laboratory of Low Dimensional Quantum Physics;
Department of Physics;
Tsinghua University;
Beijing 100084;
China;
Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices;
Renmin University of China;
Beijing 100872;
China;
Beijing National Laboratory for Condensed Matter Physics;
Institute of Physics;
Chinese Academy of Sciences;
Beijing 100190;
China;
Songshan Lake Materials Laboratory;
Dongguan 523808;
China;
Frontier Science Center for Quantum Information;
Beijing 100084;
China;