1. School of Physics and Technology, University of Jinan 1 , Shandong 250022, People's Republic of China
2. Institute of Applied Physics and Computational Mathematics 2 , Beijing 100088, China
3. College of Physics and Electronic Engineering, Northwest Normal University 3 , Lanzhou 730070, China
4. School of Materials Science and Engineering, University of Science and Technology Beijing (USTB) 4 , Beijing 100083, China
5. School of Physics and Physical Engineering, Qufu Normal University 5 , Qufu 273165, China