1. International Center for New-Structured Materials (ICNSM), Laboratory of New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
2. Multi-discipline Research Division, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
3. Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
4. State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, People's Republic of China