1. University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
2. Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, P. R. China
3. Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, P. R. China