二维铁磁体中光学螺旋依赖的轨道和自旋动力学
Optically Helicity-Dependent Orbital and Spin Dynamics in Two-Dimensional Ferromagnets
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中文总结 AI 辅助
本研究利用实时含时密度泛函理论探究圆偏振光诱导的二维铁磁体Fe3GeTe2的轨道与自旋动力学，发现其进动快于退磁并在约250阿秒内产生周期性横向响应，为阿秒尺度角动量操控提供了新途径。
中文摘要 AI 辅助
在亚飞秒时间尺度上解耦二维（2D）铁磁体超快自旋动力学中的轨道角动量（OAM）和自旋角动量（SAM）是超快磁学领域的一项挑战。在此，我们采用非共线自旋版本的实时含时密度泛函理论，研究了圆偏振光诱导的二维铁磁体Fe3GeTe2（FGT）的轨道和自旋动力学。结果表明，FGT中Fe亚晶格的退磁伴随着由圆偏振激光激发的OAM和SAM的螺旋依赖性进动。我们进一步发现，FGT中OAM和SAM的进动在几飞秒内快于退磁过程。值得注意的是，圆偏振激光能够在约250阿秒的超快时间尺度上显著诱导OAM和SAM的周期性横向响应。我们的发现为阿秒尺度的角动量操控提供了一条强有力的新途径，以相干控制二维极限下螺旋依赖的轨道和自旋动力学。
英文摘要
Disentangling orbital (OAM) and spin (SAM) angular momenta in the ultrafast spin dynamics of two-dimensional (2D) ferromagnets on subfemtoseconds is a challenge in the field of ultrafast magnetism. Herein, we employed non-collinear spin version of real-time time-dependent density functional theory to investigate the orbital and spin dynamics of 2D ferromagnets Fe3GeTe2 (FGT) induced by circularly polarized light. Our results show the demagnetization of Fe sublattice in FGT is accompanied by helicity-dependent precession of OAM and SAM excited by circularly polarized lasers. We further identify that precession of OAM and SAM in FGT is faster than the demagnetization within a few femtoseconds. Remarkably, circularly polarized lasers can significantly induce a periodically transverse response of OAM and SAM on very ultrafast timescales of ~250 attoseconds. Our finding suggests a powerful new route for attosecond regimes of the angular momentum manipulation to coherently control helicity-dependent orbital and spin dynamics in 2D limits.
