Beijing National Laboratory for Condensed Matter Physics;
Institute of Physics;
Chinese Academy of Sciences;
Beijing 100190;
China;
School of Physical Sciences;
University of Chinese Academy of Sciences;
Beijing 100190;
China;
Songshan Lake Materials Laboratory;
Dongguan 523808;
China;
Center of Materials Science and Optoelectronics Engineering;
University of Chinese Academy of Sciences;
Beijing 100049;
China;