1. School of Physics, Southeast University, Nanjing 211189, China
2. The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581, Japan
3. School of Physics and Physical Engineering, Qufu Normal University, Qufu, 273165, China
4. Advanced Functional Materials Laboratory and Department of Physics, Changshu Institute of Technology, Changshu 215500, China