1. Key Laboratory of Material Physics
2. Ministry of Education
3. School of Physics and Engineering
4. Zhengzhou University
5. Zhengzhou
6. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics
7. Peking University
8. Beijing 100871
9. China
10. Condensed Matter Physics and Materials Science
11. Brookhaven National Laboratory
12. Upton
13. USA