1. Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 P. R. China
2. School of Physical Sciences CAS Key Laboratory of Vacuum Physics University of Chinese Academy of Sciences Beijing 100190 P. R. China
3. School of Physics Beijing Institute of Technology Beijing 100081 P. R. China
4. CAS Center for Excellence in Topological Quantum Computation CAS Key Laboratory of Vacuum Physics University of Chinese Academy of Sciences Beijing 100190 P. R. China
5. Songshan Lake Materials Laboratory Dongguan Guangdong 523808 P. R. China