1. Jiyang College of Zhejiang Agriculture and Forestry University, Zhuji311800, China
2. Ames Laboratory, US Department of Energy, Ames, Iowa50011, United States
3. Department of Physics, Yantai University, Yantai264005, China
4. Department of Physics and Astronomy, Iowa State University, Ames, Iowa50011, United States
5. Department of Applied Physics, College of Science, Zhejiang University of Technology, Hangzhou310023, China
6. School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou510006, China
7. Department of Chemistry, Iowa State University, Ames, Iowa50011, United States