巨交换驱动的Eu3In2As4中最小拓扑磁体的矢量控制
Giant-exchange-driven Vectorial Control of a Minimal Topological Magnet in Eu3In2As4
AI总结：
本研究发现Eu3In2As4存在巨交换耦合，可通过磁场大小和方向调控其拓扑相，揭示了交换驱动的能带重构，确立其为调控拓扑能带结构的模型体系。
AI中文摘要：
磁性与能带拓扑的相互作用为控制物质的量子态提供了途径，但在材料中实现这种相互作用时常受限于弱交换耦合和复杂的电子结构。本研究在新预测的拓扑磁体Eu3In2As4中发现了巨交换耦合，其产生的磁化依赖能带位移可达300meV。结合其本征软磁响应，这种强耦合可通过外加磁场的大小和方向系统性调控拓扑相。研究绘制了磁拓扑相图：反铁磁拓扑绝缘体基态在中等磁场下演化为理论预测的中间2/3亚铁磁相，进一步演化为完全极化的铁磁态，该铁磁态被预测承载外尔半金属或节点线半金属，其中外尔相对应于仅含一对外尔节点的最小模型。量子振荡、反常霍尔输运和磁红外光谱一致揭示了这些相变过程中交换驱动的能带重构。理论上，磁化旋转为调控外尔节点的动量空间位置和间距提供了高效手段。这些结果确立了Eu3In2As4作为模型体系，用于探索如何利用强交换耦合以最小复杂度调控拓扑能带结构。
英文摘要：
The interplay between magnetism and band topology provides a route to controlling quantum states of matter, yet its realization in materials is often constrained by weak exchange coupling and complex electronic structures. Here, a giant exchange coupling is identified in the newly predicted topological magnet Eu3In2As4, giving rise to magnetization-dependent band shifts of up to 300 meV. Together with its intrinsically soft magnetic response, this strong cou-pling enables systematic tuning of topological phases by both the magnitude and orientation of applied magnetic fields. The magneto-topological phase diagram is mapped out in which an antiferromagnetic topological insulator ground state evolves, under modest fields, into a pro-posed intermediate 2/3-ferrimagnetic phase, and further into fully polarized ferromagnetic states predicted to host either Weyl or nodal-ring semimetals. Notably, the Weyl phase corresponds to a minimal model hosting a single pair of Weyl nodes. Quantum oscillations, anomalous Hall transport and magneto-infrared spectroscopy consistently reveal exchange-driven band recon-struction across these transitions. Rotation of the magnetization theoretically provides an effi-cient means to tune the momentum-space positions and separations of the Weyl nodes. These results establish Eu3In2As4 as a model system for exploring how strong exchange coupling can be used to control topological band structures with minimal complexity.
