On Aug. 4, Prof. Zhikun Wu (Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences), Prof. Jianxin Song (Hunan Normal University), and Prof. Huaijun Tang (Yunnan Minzu University) visited our lab for an academic exchange. They also took a group photo with Prof. Zhang and the members of our gourp. We sincerely thank them for their visit!