非相对论与相对论贡献对交变磁多铁中自旋-动量锁定和自旋光电流效应的作用
Nonrelativistic and Relativistic Contributions to Spin-Momentum Locking and Spin Photogalvanic Effect in an Altermagnetic Multiferroic
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中文总结 AI 辅助
本研究通过第一性原理计算和对称性分析，揭示了交变磁多铁BaCuF4中自旋-动量锁定的非相对论与相对论贡献，并建立了与非线性自旋输运的联系。
中文摘要 AI 辅助
交变磁多铁提供了一个平台，其中非相对论自旋-动量锁定（SML）与相对论自旋织构共存，然而厘清它们的不同起源仍然具有挑战性。在此，利用第一性原理密度泛函理论计算和自旋极化多极展开的对称性分析，我们研究了交变磁多铁BaCuF4。其主要的非相对论交变磁d波SML主要源于与极性畸变耦合的CuF6八面体旋转，因此可以通过铁电切换来反转。我们表明，自旋-轨道耦合会产生额外的自旋多极，并取决于Néel矢量方向，诱导自旋倾斜和弱铁磁性。通过利用自旋群与磁性空间群之间的群-子群关系，我们进而区分了SML中的非相对论交变磁、倾斜相关和纯相对论贡献。我们进一步表明，这种层级结构编码在非线性自旋-光电流响应中，其自旋投影选择性地探测不同起源的贡献。这些结果建立了交变磁多铁中微观自旋织构与非线性自旋输运之间的直接联系。
英文摘要
Altermagnetic multiferroics provide a platform where non-relativistic spin-momentum locking (SML) coexists with relativistic spin textures, yet disentangling their different origins remains challenging. Here, using first-principles density-functional-theory calculations and symmetry analysis of the multipolar expansion of the spin polarization, we investigate the altermagnetic multiferroic BaCuF4. Its dominant non-relativistic altermagnetic d-wave SML originates primarily from a CuF6 octahedral rotation coupled to the polar distortion and can therefore be reversed by ferroelectric switching. We show that spin-orbit coupling generates additional spin multipoles and, depending on the Neel-vector orientation, induces spin canting and weak ferromagnetism. By exploiting the group-subgroup relations between spin groups and magnetic space groups, we then distinguish non-relativistic altermagnetic, canting-associated, and purely relativistic contributions to the SML. We further show that this hierarchy is encoded in the nonlinear spin-photogalvanic response, whose spin projection selectively probes contributions of different origins. These results establish a direct connection between the microscopic spin texture and nonlinear spin transport in altermagnetic multiferroics.
发表机构
- University of Milan-Bicocca（米兰比可卡大学）
- Consiglio Nazionale delle Ricerche (CNR-SPIN)（意大利国家研究委员会）
- Institute of Physics, Polish Academy of Sciences（波兰科学院物理研究所）
- Ca’ Foscari University of Venice（威尼斯大学）
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