1. State
Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
2. Geballe
Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States
3. CAS
Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
4. Collaborative
Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China