1. Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, California 950564, USA
2. Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia, Canada B3H 4R2
3. International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
4. Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China
5. Collaborative Innovation Centre of Quantum Matter, Beijing 100871, China