1. Department of Applied Physics, Aalto University, Helsinki FI-00076, Finland
2. International Center for Quantum Materials, Peking University, Beijing 100871, China
3. Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
4. CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
5. Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China
6. WPI Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan