1. Beijing National Laboratory for Condensed Matter & Institute of Physics, Chinese Academy of Sciences, Beijing 100190, Peoples' Republic of China
2. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
3. College of Physics Science and Technology, Hebei University, Baoding 071002, Hebei Province, People's Republic of China
4. Shanxi Key Laboratory of Condensed Matter Structures and Properties, School of Science, Northwestern Polytechnical University, Xi'an 710072, China