Interplay of magnetism and electronic band topology in unconventional magnets enables the creation and fine control of novel electronic phenomena. In this work, we use scanning tunneling microscopy and spectroscopy to study thin films of a prototypical kagome magnet Fe₃Sn₂. Our experiments reveal an unusually large number of densely-spaced spectroscopic features straddling the Fermi level. These are consistent with signatures of low-energy Weyl fermions and associated topological Fermi arc surface states predicted by theory. By measuring their response as a function of magnetic field, we discover a pronounced evolution in energy tied to the magnetization direction. Electron scattering and interference imaging further demonstrates the tunable nature of a subset of related electronic states. Our experiments provide a direct visualization of how in-situ spin reorientation drives changes in the electronic density of states of the Weyl fermion band structure. Combined with previous reports of massive Dirac fermions, flat bands, and electronic nematicity, our work establishes Fe₃Sn₂ as an interesting platform that harbors an extraordinarily wide array of topological and correlated electron phenomena.

非常规磁体中磁性和电子能带拓扑结构的相互作用使得能够产生和精细控制新的电子现象。_{在这项工作中，我们使用扫描隧道显微镜和光谱学来研究原型 kagome 磁铁 Fe 3} Sn ₂的薄膜. 我们的实验揭示了跨越费米能级的异常大量的密集分布的光谱特征。这些与理论预测的低能 Weyl 费米子和相关拓扑费米弧表面态的特征一致。通过测量它们作为磁场函数的响应，我们发现了与磁化方向相关的显着能量演变。电子散射和干涉成像进一步证明了相关电子态子集的可调性质。我们的实验提供了原位自旋重定向如何驱动 Weyl 费米子带结构电子态密度变化的直接可视化。结合之前关于大质量狄拉克费米子、平带和电子向列性的报道，我们的工作建立了 Fe ₃ Sn₂作为一个有趣的平台，它包含非常广泛的拓扑和相关电子现象。