1. National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
2. Nanjing-York Joint Center of Spintronics and NanoEngineering, Department of Electronic and Physics, University of York, York YO105DD, United Kingdom
3. National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
4. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
5. Key Laboratory of Spintronics Materials, Devices and Systems of Zhejiang Province, Hangzhou 311300, China