1. Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
3. Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China
4. School of Physics Huazhong University of Science and Technology Wuhan Hubei 430074 China
5. School of Physical Sciences University of Chinese Academy of Science Beijing 100049 China