双色驱动共线反铁磁体中的宇称选择性自旋分裂
Parity-selective spin splitting in coplanar antiferromagnets via bichromatic driving
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中文总结 AI 辅助
该研究针对反铁磁体自旋分裂受本征对称性限制的问题，提出利用双色弗洛凯驱动调控自旋分裂宇称的方法，揭示了谐波层级与自旋分裂宇称的关系，为自旋调控提供了新途径。
中文摘要 AI 辅助
宇称是反铁磁体（AFMs）中与动量相关的自旋分裂的核心特征，然而本征晶体对称性通常将该分裂限制为仅偶宇称或奇宇称，阻碍了灵活的自旋调控。本文利用共线反铁磁体，证明双色（ω–nω）弗洛凯驱动提供了规避该约束的自然途径，该机制可产生静态反铁磁体或单色驱动下无法实现的非对称自旋纹理。针对所研究的特定反铁磁体，本文揭示了自旋分裂宇称和谐波层级间的简洁关系：ω–2ω场可产生高度可调的奇宇称及混合宇称自旋分裂，而高阶谐波（n≥3）仅产生偶宇称态；宏观磁化强度也可通过特定驱动协议和谐波n进行切换。这些不同的自旋分裂态在光猝灭后产生的宏观自旋电流中表现出质的差异，这一明确的输运特征可作为自旋角分辨光电子能谱直接观测的补充。
英文摘要
Parity is a central characteristic of momentum-dependent spin splitting in antiferromagnets (AFMs). Yet, intrinsic crystal symmetries typically restrict the splitting to either even or odd parity, preventing flexible spin control. Using a coplanar AFM, we demonstrate that bichromatic ($ω$--$nω$) Floquet driving offers a natural way to bypass this constraint. This mechanism generates asymmetric spin textures unattainable in static AFMs or under monochromatic driving. For the specific AFM considered here, we reveal an elegant relation between spin-splitting parity and harmonic hierarchy: $ω$--$2ω$ fields generate highly tunable odd- and mixed-parity spin splittings, whereas higher-order harmonics ($n \ge 3$) exclusively produce even-parity states. The macroscopic magnetization can also be toggled via the specific driving protocol and harmonic $n$. These distinct spin splitting states manifest in qualitatively different macroscopic spin currents generated after an optical quench---a definitive transport signature complementing direct visualization via spin- and angle-resolved photoemission spectroscopy.
