1. Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, P.R. China
2. College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, P.R. China
3. School of Physical Sciences and CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China
4. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
5. Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, P.R. China