1. Department of Physics and Astronomy, University of Tennessee 1 , Knoxville, Tennessee 37996, USA
2. Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences 2 , Hefei, Anhui 230031, China
3. School of Microelectronics and Control Engineering, Changzhou University 3 , Changzhou, Jiangsu 213001, China