1. State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
2. Lab for Advanced Materials and Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100083, China
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, U.K.
5. Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
6. Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou, Zhejiang 31008, China
7. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
8. ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
9. Frontier Science Center for Quantum Information, Beijing 100084, China