论文标题
激光诱导的反电磁化的旋转角动量在哪里？
Where does the spin angular momentum go in laser induced demagnetisation?
论文作者
论文摘要
3 $ d $磁铁中超快脱氧化的动力学因旋转$ {\ v s} $和轨道$ {\ v l} $角动量而变得复杂，并具有微观机制，通过这些机制将磁矩重新分配到晶格，以及在什么时间范围内，还可以分辨出来。采用最新的时间依赖性密度函数理论，我们解开了这两个矩的动力学。利用将旋转轨道（SO）分开的超短（5〜fs）脉冲和直接的光激发时间尺度分开，我们演示了一种两步的显微镜机制：（i）初始损失$ {\ v l} $，由于激发激励，由于$ {\ v l} $ {$ {$} $ c} $ {$ r} $ {$ r} $ r} $ r} $ c {在随后的（$> 15 $ 〜fs）中，因此引起的自旋flip弹药。我们还表明，要看到$ {\ v s} $的明确传输到$ {\ v l} $需要短脉冲。
The dynamics of ultrafast demagnetisation in 3$d$ magnets is complicated by the presence of both spin ${\v S}$ and orbital ${\v L}$ angular momentum, with the microscopic mechanism by which the magnetic moment is redistributed to the lattice, and at what time scales, yet to be resolved. Employing state-of-the-art time dependent density function theory we disentangle the dynamics of these two momenta. Utilising ultra short (5~fs) pulses that separate spin-orbit (SO) and direct optical excitation time scales, we demonstrate a two-step microscopic mechanism: (i) an initial loss of ${\v L}$ due to laser excitation, followed post pulse by (ii) an increase of ${\v L}$ as ${\v S}$ transfers to ${\v L}$ during subsequent ($> 15$~fs) SO induced spin-flip demagnetisation. We also show that to see an unambiguous transfer of ${\v S}$ to ${\v L}$ a short pulse is required.
