1. National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, and Department of Physics, Nanjing University, Nanjing 210093, China
2. School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, Zhejiang, 310018, China
3. College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
4. Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China