1. National Laboratory of Solid States Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
2. College of Science, China University of Petroleum (East China), Qingdao 266580, China
3. School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
4. National Laboratory of Solid States Microstructures and Research Institute of Superconductor Electronics, Nanjing University, Nanjing 210093, China
5. College of Electronic Engineering, Nanjing Xiaozhuang University, Nanjing 211171, China