1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
2. National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
3. Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
4. School of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou 450044, China