1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics; Chinese Academy of Sciences; Beijing 100190 China
2. Bejing Institute of Nanoenrgy and Nanosystems; Chinese Academy of Sciences, National Center for Nanoscience and Technology (NCNST); Beijing 100190 China
3. School of Physical Sciences; University of Chinese Academy of Sciences; Beijing 100083 China
4. Collaborative Innovation Center of Quantum Matter; Beijing Key Laboratory for Nanomaterials and Nanodevices; Beijing 100190 China