1. Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications; School of Materials Science and Engineering; Beijing Institute of Technology; Beijing 100081 P. R. China
2. Institute of Applied Physics and Computational Mathematics; Beijing 100088 P. R. China
3. Institute of Physics; Chinese Academy of Sciences; Beijing 100190 P. R. China
4. Department of Physics; Beihang University; Beijing 100191 P. R. China
5. Beijing Synchrotron Radiation Facility (BSRF); Beijing 100049 P. R. China