1. School of Physics and Electronic Engineering, Chongqing Normal University 1 , Chongqing 401331, People's Republic of China
2. CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology 2 , Beijing 100190, People's Republic of China
3. School of Physics, Central South University 3 , Changsha 410083, People's Republic of China
4. School of Physics and Chemistry, Hunan First Normal University 4 , Changsha 410205, People's Republic of China
5. Beijing Sinoagg Tech Co., Ltd 5 , No.33 Zique Rd., Haidian District, Beijing, People's Republic of China