1. State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 P. R. China
2. Institute for Advanced Studies (IAS) Wuhan University Wuhan 430072 P. R. China
3. State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 P. R. China
4. School of Physical Science and Technology ShanghaiTech University Shanghai 201210 P. R. China
5. ShanghaiTech Laboratory for Topological Physics Shanghai 201210 P. R. China
6. Center for Transformative Science ShanghaiTech University Shanghai 201210 P. R. China
7. Shanghai high repetition rate XFEL and extreme light facility (SHINE) ShanghaiTech University Shanghai 201210 P. R. China
8. Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
9. Stanford Synchrotron Radiation Lightsource SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
10. National Laboratory of Solid State Microstructures and School of Physics Nanjing University Nanjing 210093 P. R. China
11. Clarendon LaboratoryDepartment of Physics University of Oxford Oxford OX1 3PU UK