1. Department of Physics Science and Technology, Kunming University, Kunming 650214, China
2. Department of Physics and Astronomy, Yunnan University, Kunming 650504, China
3. Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
4. National Laboratory of Solid State Microstructures, Department of Physics, and Collaborative, Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China