1. Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Materials, College of Physics, Chongqing University, Chongqing 401331, P. R. China
2. Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, United States
3. Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Science, Chongqing 400714, P. R. China
4. University of Chinese Academy of Sciences, Beijing 100044, P. R. China
5. Department of Physics, Chun Yuan Christian University, Chung-Li District, Taoyuan City 32023, Taiwan
6. Analytical and Testing Center of Chongqing University, Chongqing 401331, P. R. China