1. Department of Applied Physics, School of Science, Hunan University of Technology, Zhuzhou 412007, China
2. School of Information Engineering, Huangshan University, Huangshan 245041, China
3. Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009-26, Beijing 100088, China
4. Hebei Key Lab of Optic-electronic Information and Materials, The College of Physics Science and Technology, Hebei University, Baoding 071002, China