1. School of Physics and Optoelectronic Engineering, Ludong University, Yantai, Shandong, 264025, P. R. China
2. Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
3. Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Education University, Guiyang, Guizhou, 550018, P. R. China
4. Department of Physics, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China