发表机构
Nagoya University（名古屋大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过共同模型计算表明，交变磁体电荷-自旋转换各向异性主要源于电子自旋劈裂，磁振子通道贡献微弱，但其对子晶格微扰的线性响应为交变磁序所独有，且无需单畴样品即可测量。
AI 中文摘要
交变磁体在不具有净磁化或自旋-轨道耦合的情况下获得动量依赖的自旋劈裂。这引发了一个问题：输运各向异性源于电子还是磁振子，以及磁振子介导的通道是否能区分交变磁体与常规反铁磁体。我们在一个共同模型中计算了金属铁磁体、反铁磁体和交变磁体的自旋分辨电导率，其中自旋对角通道采用磁振子自能处理，自旋翻转通道则处理到电子-磁振子耦合的领头阶。电荷-自旋转换的各向异性由电子自旋劈裂主导，磁振子支的贡献仅占极小部分。磁振子介导的自旋翻转通道在$C_{4}$下为偶对称，因此在一阶各向异性中不携带特征信号，其本身无法区分交变磁体与常规反铁磁体。然而，该通道对降低体$B_{1g}$对称性的子晶格选择性微扰呈线性响应。由此产生的磁化率在反铁磁体中恒为零，在铁磁体中很小，而在交变磁体中为有限值，其中电子各向异性将自旋与子晶格联系在一起，因此在无净磁化的磁体中，该响应为交变磁序所独有。由于该响应在磁畴指标下为偶对称，因此无需制备单磁畴样品即可测量。
英文摘要
Altermagnets acquire a momentum-dependent spin splitting without net magnetization or spin-orbit coupling. This raises the question of whether the transport anisotropy originates in the electrons or the magnons, and whether the magnon-mediated channel distinguishes an altermagnet from a conventional antiferromagnet. We compute the spin-resolved conductivity of a metallic ferromagnet, antiferromagnet, and altermagnet within a common model, treating the spin-diagonal channel with the magnon self-energy and the spin-flip channel to leading order in the electron-magnon coupling. The anisotropy of the charge-spin conversion is dominated by the electronic spin splitting, the magnon branches contributing only marginally. The magnon-mediated spin-flip channel is even under $C_{4}$, so it carries no signature at first order in the anisotropy and cannot on its own distinguish an altermagnet from a conventional antiferromagnet. It does, however, respond linearly to a sublattice-selective perturbation that lowers the bulk $B_{1g}$ symmetry. The resulting susceptibility vanishes identically in the antiferromagnet, is small in the ferromagnet, and is finite in the altermagnet, where the electronic anisotropy ties spin and sublattice together, so that among magnets with no net magnetization it is unique to altermagnetic order. Being even in the magnetic domain index, this response can be measured without preparing a single magnetic-domain sample.
