1. Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui, China
2. State Key Laboratory of Silicon Materials and Department of Physics, Zhejiang University, Hangzhou 310027,
China
3. Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309, USA
4. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China