1. Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
2. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
3. Department of Physics, Nanjing University, Nanjing 210093, China
4. York-Nanjing Joint Center (YNJC) for Spintronics and Nano-Engineering, Department of Electronics and Physics, University of York, York YO10 5DD, United Kingdom
5. Key Laboratory of Spintronics Materials, Devices and Systems of Zhejiang Province, 9 Lixin Road, Linan, Hangzhou 311300, China