Magnetic interactions in combination with nontrivial band structures can give rise to several exotic physical properties such as a large anomalous Hall effect, the anomalous Nernst effect, and the topological Hall effect (THE). Antiferromagnetic (AFM) materials exhibit the THE due to the presence of nontrivial spin structures. EuCuAs crystallizes in a hexagonal structure with an AFM ground state (Néel temperature ∼ 16 K). In this work, we observe a large topological Hall resistivity of ∼7.4 μΩ-cm at 13 K which is significantly higher than the giant topological Hall effect of Gd₂PdSi₃ (∼3 μΩ-cm). Neutron diffraction experiments reveal that the spins form a transverse conical structure during the metamagnetic transition, resulting in the large THE. In addition, by controlling the magnetic ordering structure of EuCuAs with an external magnetic field, several fascinating topological states such as Dirac and Weyl semimetals have been revealed. These results suggest the possibility of spintronic devices based on antiferromagnets with tailored noncoplanar spin configurations.

中文翻译：

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磁性与拓扑之间的相互作用：反铁磁拓扑绝缘体中的大拓扑霍尔效应，EuCuAs

磁相互作用与非平凡的能带结构相结合可以产生一些奇异的物理特性，例如大反常霍尔效应、反常能斯特效应和拓扑霍尔效应 (THE)。由于存在非平凡的自旋结构，反铁磁 (AFM) 材料表现出 THE。EuCuAs 结晶为具有 AFM 基态的六方结构（奈尔温度 ∼ 16 K）。在这项工作中，我们在 13 K 时观察到 ∼7.4 μΩ-cm 的大拓扑霍尔电阻率，这明显高于 Gd ₂ PdSi _{3的巨大拓扑霍尔效应}（~3 μΩ-cm）。中子衍射实验表明，自旋在变磁转变过程中形成横向锥形结构，导致较大的 THE。此外，通过用外部磁场控制 EuCuAs 的磁有序结构，揭示了狄拉克和外尔半金属等几种迷人的拓扑态。这些结果表明，基于具有定制的非共面自旋配置的反铁磁体的自旋电子器件的可能性。