1. Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou 310058, China
2. Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310058, China
3. Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
4. State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310058, China
5. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
6. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
7. Physics Department, Technical University of Munich, 80333 Munich, Germany