1. Department of Materials Science and Engineering; College of Engineering; Peking University; Beijing 100871 P. R. China
2. Center for Nanochemistry (CNC); Beijing Science and Engineering Center for Nanocarbons; Beijing National Laboratory for Molecular Sciences; College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 P. R. China
3. Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials; Faculty of Physics and Electronic Technology; Hubei University; Wuhan 430062 P. R. China
4. Institute of Physics; Chinese Academy of Sciences and Beijing National Laboratory for Condensed Matter Physics; Beijing 100190 P. R. China
5. Collaborative Innovation Center of Quantum Matter; Beijing 100190 P. R. China