1. Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2. Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Science, Shanghai 200050, China
3. Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
4. Department of Physics, Fudan University, Shanghai 200433, China