1. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
2. Departments of Materials and Physics and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, United Kingdom
3. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
4. State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China
5. Collaborative Innovation Center of Quantum Matter, Beijing 100190, P. R. China
6. Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States