1. Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, P.R. China
2. Department of Physics, University of Science and Technology of China, Hefei 230026, P.R. China
3. Department of Physics, School of Physics and Materials Science, Anhui University, Hefei 230601, P.R. China