1. State Key Laboratory for Mesoscopic Physics and Department of Physics Peking University Beijing 100871 P. R. China
2. State Key Laboratory of Information Photonics and Optical Communications and School of Science Beijing University of Posts and Telecommunications Beijing 100876 P. R. China
3. Beijing Key Laboratory for Magnetoelectric Materials and Devices Peking University Beijing 100871 P. R. China
4. Collaborative Innovation Center of Quantum Matter Beijing 100871 P. R. China
5. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing 100871 P. R. China