1. National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
2. Information Hub , Hong Kong University of Science and Technology (Guangzhou) , Guangzhou 511458 , China
3. School of Physical Science and Technology , Soochow University , Suzhou 215006 , China
4. Hong Kong University of Science and Technology , Hong Kong , China