1. Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Ministry of Education, Beijing 100124, China
2. State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China
3. Faculty of Information Technology, School of Microelectronics, Beijing University of Technology, Beijing 100124, China
4. Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China