1. Department of Physics, School of Physics and Materials Science, Nanchang University, Nanchang 330031, China
2. Department of Materials, School of Physics and Materials Science, Nanchang University, Nanchang 330031, China
3. Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu, China