1. Aerospace Information Research Institute, Chinese Academy of Sciences, No.9 Dengzhuang South Road, Haidian District, Beijing 100094, China
2. School of Electronic, Electrical and Communication Engineering, University of the Chinese Academy of Sciences, Beijing 100049, China
3. Department of Physics, University of Basel, 4056 Basel, Switzerland
4. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, No.8, 3rd South Street, Zhongguancun, Haidian District, Beijing 100190, China
5. School of Physical Sciences, University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
6. Songshan Lake Materials Laboratory, Dongguan 523808, China