Electron Doping and Physical Properties in the Ferromagnetic Semimetal Co₃Sn_2–xSb_xS₂

The ferromagnetic shandite Co₃Sn₂S₂ has attracted great attention in physics and chemistry communities owing to its Kagome net, magnetism, and topological property. Here, for the first time, we report the effect of Sb doping on the crystal structure, magnetic interaction, and transport behavior of this ferromagnetic Weyl semimetal. A relatively low doping limit has been determined as x = 0.1 in a Co₃Sn_2–xSb_xS₂ system. Single-crystal X-ray diffraction indicates that the Sb doping shows a preferred occupation at the Sn sites between Kagome layers (Sn(1)) rather than the intralayer sites (Sn(2)), leading to the anisotropic contraction of the lattice. The ferromagnetic interaction is weakened upon Sb doping with the Curie temperature decreased from 172 to 146 K, which resulted from the shifting of the Fermi level toward high energy. Due to the electron injection, the Sb-doped sample shows the declined thermoelectric property with the reduced absolute value of the Seebeck coefficient compared to the parent compound. The anomalous Hall effect is still maintained in Co₃Sn_1.9Sb_0.1S₂ with the increased anomalous Hall resistivity based on the measurement on polycrystalline samples. Our work provides a new electron doping system to understand the interplay between the magnetism and quantum properties of this Weyl semimetal.