Title: Dynamical Generation of Higher-order Spin-Orbit Couplings, Topology and Persistent Spin Texture in Light-Irradiated Altermagnets Show Chinese title

Title: 光辐照反铁磁中的高阶自旋-轨道耦合、拓扑和持久自旋纹理的动力学生成

Abstract: Altermagnets have been identified as the third category of magnetic materials, exhibiting momentum-dependent spin splitting characterized by even powers of momentum. In this study, we show that when subjected to elliptically polarized light, these materials serve as an exemplary framework for the dynamic generation of topological bands featuring higher-order spin-orbit coupling (SOC). Notably, while the generated Zeeman field remains invariant to the particular altermagnetic ordering, the induced higher-order SOCs are related to the magnitude and symmetry of the altermagnetic order. Specifically, we show that an altermagnet exhibiting $k^n$-spin splitting can generate spin-orbit couplings up to $k^{n-1}$. In the limit of circularly polarized light, the only correction is $k^{n-1}$, with all lower-order contributions being nullified. Interestingly, light-induced SOCs significantly impact the low-energy band topology, where their Chern numbers change by $\Delta C =\pm 1,2,3$ for $d,g,f$-wave altermagnets. Finally, we find a critical field in which a persistent spin texture is realized, a highly desirable state with predicted infinite spin lifetime. Our work showcases light as a powerful, controllable tool for engineering complex and exciting phenomena in altermagnets. Show Chinese abstract

Abstract: 反磁材料已被确认为第三类磁性材料，其特征是动量相关的自旋劈裂，由动量的偶数次幂表征。 在这项研究中，我们展示了当暴露于椭圆偏振光下时，这些材料成为动态生成拓扑能带的典型框架，这些能带具有高阶自旋轨道耦合（SOC）。 值得注意的是，虽然产生的Zeeman场对于特定的反磁序保持不变，但诱导的高阶SOC与反磁序的大小和对称性相关。 具体而言，我们证明了一个表现出$k^n$自旋劈裂的反磁材料可以生成高达$k^{n-1}$的自旋轨道耦合。 在圆偏振光的极限情况下，唯一的修正为$k^{n-1}$，所有低阶贡献都被抵消。 有趣的是，光诱导的SOC显著影响低能带拓扑结构，在$d,g,f$波反磁体中，其Chern数变化$\Delta C =\pm 1,2,3$。 最后，我们发现了一个临界场，在此场中实现了持续的自旋纹理，这是一种具有预测无限自旋寿命的高度理想状态。 我们的工作展示了光作为一种强大的可控工具，在反磁体中工程化复杂而令人兴奋的现象。