1. National Laboratory of Solid States Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
2. National Laboratory of Solid States Microstructures, Research Institute of Superconductor Electronics, Nanjing University, Nanjing 210093, China
3. College of Electronic and Information Engineering, Jinling Institute of Technology, Nanjing 211169, China
4. College of Electronic Engineering, Nanjing Xiaozhuang University, Nanjing 211171, China