1. Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic Physics
2. School of Physics
3. Xi'an Jiaotong University
4. Xi'an 710049
5. China
6. Department of Applied Biology and Chemical Technology
7. The Hong Kong Polytechnic University
8. Kowloon
9. Center for Functional Nanomaterials
10. Brookhaven National Laboratory
11. New York 11973
12. USA
13. School of Materials Science and Engineering
14. National Institute for Advanced Materials
15. Nankai University
16. Tianjin 300350
17. Beijing National Laboratory for Condensed Matter Physics
18. Institute of Physics
19. Chinese Academy of Sciences
20. Beijing