AI 中文总结
本研究构建二维d波交替磁体四带紧束缚模型，区分三种自旋轨道耦合作用，揭示其可稳定陈绝缘体相，实现大光学霍尔电导率、圆二色性及门控霍尔响应符号反转，明确界面SOC机制的互补作用。
AI 中文摘要
交替磁体结合了补偿共线磁序与动量依赖的自旋分裂，为实现无净铁磁矩的横向电子及光学响应提供了途径。我们为二维d波交替磁体构建了严格周期性的四带紧束缚模型，并区分了三种自旋轨道耦合（SOC）通道的作用：均匀Rashba SOC、子晶格交错Rashba相互作用，以及键交错SOC。在无SOC时，d波动力学各向异性在正交布里渊区边界产生自旋极化狄拉克点，这些狄拉克点由交替磁体的四重自旋群对称性关联。均匀Rashba SOC混合自旋 sector并移动这些节点，但保留了禁止积分霍尔响应的反幺正对称性；子晶格交错Rashba项破坏该对称性并激活横向光学响应，而键交错SOC提供使边界节点打开能隙的质量。三者的共同作用产生强贝里曲率热点，且在窄参数窗口内形成具有陈数C=-2的孤立低两带流形，在此考虑的代表性参数下可稳定陈绝缘体相。通过协变速度久保计算，我们表明大光学霍尔电导率与圆二色性远超出非零陈数区域，且受SOC诱导的避免交叉与对称性破缺调控；进一步发现，载流子掺杂通过泡利阻塞和贝里曲率热点的占据强烈修改共振与直流霍尔响应，实现门控符号反转。这些结果明确了不同界面SOC机制在补偿二维磁体中产生拓扑与可调磁光活性的互补作用。
英文摘要
Altermagnets combine compensated collinear magnetic order with momentum-dependent spin splitting, providing a route to transverse electronic and optical responses without a net ferromagnetic moment. We develop a strictly periodic four-band tight-binding model for a two-dimensional d-wave altermagnet and distinguish the roles of three spin orbit coupling (SOC) channels: uniform Rashba SOC, a sublattice-staggered Rashba interaction, and bond-staggered SOC. In the absence of SOC, the d-wave kinetic anisotropy produces spin-polarized Dirac points on orthogonal Brillouin-zone boundaries, related by the altermagnetic fourfold spin-group symmetry. Uniform Rashba SOC mixes the spin sectors and shifts these nodes but preserves the antiunitary symmetry that forbids an integrated Hall response. The sublattice-staggered Rashba term breaks this symmetry and activates transverse optical response, whereas the bond-staggered SOC provides the mass that gaps the boundary nodes. Their combined action generates strong Berry-curvature hot spots and, within a narrow parameter window, an isolated lower two-band manifold with Chern number C=-2. For the representative parameters considered here it is possible to stabilize a Chern insulator phase. Using covariant-velocity Kubo calculations, we show that large optical Hall conductivity and circular dichroism extend well beyond the nonzero-Chern region and are controlled by SOC-induced avoided crossings and symmetry breaking. We further find that carrier doping strongly modifies the resonant and dc Hall responses through Pauli blocking and the occupation of Berry-curvature hot spots, enabling gate-controlled sign reversals. These results identify the complementary roles of distinct interfacial SOC mechanisms in producing topology and tunable magneto-optical activity in compensated two-dimensional magnets.
Comments16 pages, 9 figures
