1. The Key Laboratory of Cluster Science of Ministry of Education
2. School of Physics
3. Beijing Institute of Technology
4. 100081 Beijing
5. China
6. Institute of Physics
7. Chinese Academy of Sciences
8. 100190 Beijing
9. Institute for Frontier Materials
10. Deakin University
11. 3216 Victoria
12. Australia
13. CAS Key Laboratory of Standardization and Measurement for Nanotechnology
14. CAS Center for Excellence in Nanoscience
15. National Center for Nanoscience and Technology