1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2. College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
3. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
4. Department of Physics, National Chung Cheng University, Chiayi 621301, Taiwan
5. National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 300092, Taiwan
6. Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden 01187, Germany
7. Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China