1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
2. Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. College of Physics, Jilin University, Changchun 130012, China
5. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
6. X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
7. Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States