1. School of Physics and Wuhan National High Magnetic Field Centre, Huazhong University of Science and Technology, Wuhan 430074, P.R. China
2. Zhengzhou University of Light Industry, School of Physics and Electrical Engineering, Zhengzhou 450002, Henan, P.R. China
3. School of Physics, Wuhan University, Wuhan 430072, P.R. China