1. State Key Laboratory of Spintronics Devices and Technologies, School of Electronic Science and Engineering, Nanjing University 1 , Nanjing 210023, China
2. Institute of Nanosurface Science and Engineering, College of mechatronics and control engineering, Shenzhen University 2 , Shenzhen 518060, China
3. National Key Laboratory of Radio Frequency Heterogeneous Integration, Shenzhen University 3 , Shenzhen 518060, China