Topological materials are expected to show distinct transport signatures due to their unique band-inversion character and band-crossing points. However, the intentional modulation of such topological responses by experimentally feasible means is less explored. Here, an unusual elevation of anomalous Hall effect (AHE) is obtained in electron(Ni)-doped magnetic Weyl semimetal Co 3-x Ni x Sn 2 S 2 , showing peak values of anomalous Hall-conductivity, Hall-angle and Hall-factor at a relatively low doping level of x = 0.11. The separation of intrinsic and extrinsic contributions to total AHE using TYJ scaling model indicates that such significant enhancement is dominated by the intrinsic mechanism of electronic Berry curvature. Theoretical calculations reveal that compared with the Fermi-level shifting from electron filling, a usually overlooked effect of doping, i.e., local disorder, imposes a striking effect on broadening the bands and narrowing the inverted gap, and thus results in an elevation of the integrated Berry curvature.Our results not only realize the enhancement of AHE in a magnetic Weyl semimetal, but also provide a practical design principle to modulate the bands and transport properties in topological materials, by exploiting the disorder effect of doping.

Anomalous Hall effect (AHE) can be induced by intrinsic mechanism due to the band Berry phase and extrinsic one arising from the impurity scattering. The recently discovered magnetic Weyl semimetal Co3Sn2S2 exhibits a large intrinsic anomalous Hall conductivity (AHC) and a giant anomalous Hall angle (AHA). The predicted energy dependence of the AHC in this material exhibits a plateau at 1000 Ω-1 cm-1 and an energy width of 100 meV just below EF, thereby implying that the large intrinsic AHC will not significantly change against small-scale energy disturbances such as slight p-doping. Here, we successfully trigger the extrinsic contribution from alien-atom scattering in addition to the intrinsic one of the pristine material by introducing a small amount of Fe dopant to substitute Co in Co3Sn2S2. Our experimental results show that the AHC and AHA can be prominently enhanced up to 1850 Ω-1 cm-1 and 33%, respectively, owing to the synergistic contributions from the intrinsic and extrinsic mechanisms as distinguished by the TYJ model. In particular, the tuned AHA holds a record value in low fields among known magnetic materials. This study opens up a pathway to engineer giant AHE in magnetic Weyl semimetals, thereby potentially advancing the topological spintronics/Weyltronics.

Co 3 Sn 2 S 2 , a quasi-two-dimensional system with kagome lattice, has been found as a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co 3 Sn 2 S 2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient K u up to 8.3 × 10 5 J m -3 , which indicates that it is extremely difficult to align the small moment of 0.29 μ B /Co on the kagome lattice from c axis to ab plane. The out-of-plane angular dependences of Hall conductivity further reveal strong anisotropies in Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For in-plane situation, the longitudinal and transverse measurements for both I // a and I  a cases show that the transport on the kagome lattice is isotropic. These results provide essential understanding on the magnetization and transport behaviors for the magnetic Weyl semimetal Co 3 Sn 2 S 2 .