1. Guangxi Key Laboratory of Automatic Detecting Technology and Instrument, Guilin University of Electronic Technology, Guilin 541004, People’s Republic of China
2. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
3. Songshan Lake Material Laboratory, Dongguan, Guangdong 523808, People’s Republic of China
4. University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China