1. International
Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People’s Republic of China
2. Collaborative Innovation Center of Quantum Matter, Beijing 100871, People’s Republic of China
3. Physics
Department, The University of Hong Kong, Hong Kong, People’s Republic of China
4. Center
of Electron Microscopy, State Key Laboratory of Silicon Materials,
Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China
5. State
Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People’s Republic of China