1. National Laboratory of Solid-State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
2. Department of Applied Physics, College of Science, Nanjing Forestry University, Nanjing 210037, China
3. School of Materials Science and Engineering, Jingdezhen University of Ceramics, Jingdezhen 333001, China