Hong-Jun Gao, Senhao Lv, Hui Guo, Jiangang Yang, Ke Zhu, Lin Zhao, Yan Li, Roger Guzman, Xianghua Kong, Guoyu Xian, Qiuzhen Cheng, Qi Zheng, Li Huang, Yuqing Xing, Hui Chen, Zhen Zhao, Qi Qi, Lulu Pan, Linxuan Song, Chengmin Shen, Dongliang Zhao, Xiao Lin, Stephen Pennycook, Wu Zhou, Wei Ji, Jun He, Xingjiang Zhou, and Haitao Yang
As a ferromagnetic topological semimetal with a strong anomalous Hall effect (AHE), Co3Sn2S2 has been extensively explored for manipulating the topological state via the changed magnetic order as well as device applications connecting dissipationless spin and charge transport1-3. However, the main challenge is the improvement of the crystal quality, which is crucial for enhancing physical properties including AHE, carrier mobility, and magnetoresistance4,5. Here, we report the synthesis of ultra pure Co3Sn2S2 single crystals with an ultra low impurity density by an innovative crystal-sourced chemical vapor transport (CS-CVT) approach, achieving ultrahigh anomalous Hall angle (AHA) of 40%, carrier mobility and magnetoresistance (MR) of 10490 cm2V-1s-1 and 2500%, respectively. These values represent a huge improvement on previously reported highest values of either pristine or doped Co3Sn2S2 (of 33%, 2600 cm2V-1s-1, and 180% respectively)4,6. Equally importantly, the anomalous Hall conductivity (AHC) of our crystals reached 1600 Ω-1cm-1, which is larger than the theoretically predicted value of 1310 Ω-1cm-1 from the integral of Berry curvature7. Observation of an ultranarrow flat band and topological surface states near the Fermi level provides good microscopic understanding of this gigantic anomalous Hall effect. Our high-quality magnetic topological materials are expected to facilitate a full understanding of the strong electronic correlation and may perhaps lead to the discovery of a quantum AHE in the 2D limit.