1. Key Laboratory of Materials Physics
2. Institute of Solid State Physics
3. Chinese Academy of Sciences
4. Hefei 230031, P. R. China
5. Department of Chemical Engineering
6. New Mexico State University
7. Las Cruces, USA
8. State Key Laboratory of Electronic Thin Films and Integrated Devices
9. University of Electronic Science and Technology of China
10. Chengdu 610054, P. R. China
11. High Magnetic Field Laboratory