1. Department of Physics, School of Physics and Materials Science, Guangzhou University, Guangzhou510006, People’s Republic of China
2. Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, P. R. China
3. Huangpu Research & Graduate School of Guangzhou University, Sino-Singapore Guangzhou Knowledge City, Huangpu District, Guangzhou510555, People’s Republic of China
4. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, P. R. China