本工作结合第一性原理计算、角分辨光电子能谱和磁输运测量，确立了呼吸型kagome磁体LaCrGe₃的磁性Weyl半金属态，并揭示了呼吸晶格畸变对费米能级附近Weyl拓扑电子态的增强作用。基于此，通过外磁场驱动磁矩发生连续转动，实现了Weyl点在动量空间中的移动与演化，并获得了与Berry曲率演化相一致的角度可调反常霍尔响应。该研究利用磁场驱动自旋取向实现了拓扑态与拓扑电子输运的有效调控，为发展外场可控的拓扑自旋电子学和量子功能器件提供了新的材料平台与物理基础。

This work establishes the breathing-kagome ferromagnet LaCrGe₃ as a magnetic Weyl semimetal by combining first-principles calculations, angle-resolved photoemission spectroscopy, and magnetotransport measurements, and reveals the enhancement of Weyl topological states near the Fermi level by the breathing lattice. Furthermore, the continuous rotation of magnetic moments from the c axis toward the ab plane under an external magnetic field drives the motion and evolution of Weyl points in momentum space, producing a highly tunable angle-dependent anomalous Hall response consistent with the evolution of Berry curvature. These results demonstrate an effective modulation for topological states and topological transport through magnetic-field-driven spin orientation, providing a new material platform and physical basis for field-tunable topological spintronics and quantum functional devices.

研究发现，Fe掺杂能抑制外禀散射，使Co₁.₈Fe₀.₂MnGa在2300K范围内的反常霍尔电导率完全源于内禀贝里曲率；而Ni掺杂样品则始终兼具内禀与外禀贡献。实验表明，反常霍尔角与纵向电导率呈双曲线关系，说明高霍尔角既可在超洁净体系实现，也可在强无序坏金属区获得。研究提出，外禀贡献由缺陷浓度调控：少量缺陷通过斜散射增强外禀信号，过高缺陷则缩短载流子寿命、抑制外禀效应。此外，多晶Co₂MnGa因弱各向异性和Weyl费米子高迁移性，性能接近单晶，有利于器件应用。
Fe doping suppresses extrinsic scattering, making the anomalous Hall conductivity of Co₁.₈Fe₀.₂MnGa purely intrinsic (Berry-curvature dominated) over the entire 2 300 K range, whereas all Ni-doped samples show both intrinsic and extrinsic contributions. The anomalous Hall angle versus longitudinal conductivity follows a hyperbolic relation with a minimum, indicating that a high Hall angle can be achieved either in ultraclean systems or in strongly disordered bad-metal hopping regimes. The extrinsic Hall contribution is governed by a generalized defect concentration: a moderate level enhances skew-scattering, while excessive defects shorten carrier lifetime and suppress the extrinsic signal. Moreover, polycrystalline Co₂MnGa, benefiting from weak anisotropy and high Weyl-fermion mobility, exhibits transport properties close to those of single crystals, lowering the barrier for device applications.

本工作以铁磁Heusler化合物为平台，利用空间群变换引起的对称性破缺，发现了一种名为“拓扑伞”的拓扑非平庸电子能带结构。该结构由二重简并的自旋向上能带和三重简并的自旋向下能带构成，源于晶体场劈裂、自旋劈裂和自旋轨道耦合的协同作用。依靠其较平坦的色散和线性能带交叉，该伞状电子结构可有效调控拓扑性质，将Heusler化合物的反常霍尔电导率从98 Ω⁻¹cm⁻¹大幅提升至3032 Ω⁻¹cm⁻¹。
Here, using ferromagnetic Heusler compounds as a platform, we exploit symmetry breaking induced by space group transformations to discover a topologically nontrivial electronic band structure termed the "topological umbrella." This structure consists of doubly degenerate spin-up bands and triply degenerate spin-down bands, arising from the interplay of crystal field splitting, spin splitting, and spin–orbit coupling. By virtue of its relatively flat dispersion and linear band crossings, this umbrella-shaped electronic structure enables effective tuning of topological properties, dramatically enhancing the anomalous Hall conductivity of Heusler compounds from 98 Ω⁻¹cm⁻¹ to 3032 Ω⁻¹cm⁻¹.