1. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2. CAS Center of Excellence in Topological Quantum Computation and College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
3. School of Materials Science and Engineering, MOE Key Laboratory of Micro-Systems and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin 150080, China
4. State Key Laboratory of Mesoscopic Physics, School of Physics and Collaborative Innovation Center Quantum Matter, Peking University, Beijing 100871, China
5. Department of Physics, Renmin University of China, Beijing 100872, China