Hot spin spots in the laser-induced demagnetization
Hot spin spots in the laser-induced demagnetization
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DOI：
10.1063/1.3693402
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发表时间：
2012-03-01
期刊：
影响因子：
1.6
通讯作者：
Zhang, G. P.
中科院分区：
文献类型：
--
作者：
Si, M. S.;Zhang, G. P.
激光诱导飞秒磁性或飞磁学同时依赖于两个不同的贡献：(a)激光场和磁系统之间的光偶极相互作用（ODI）和(b)两个过渡态之间的自旋期望值变化（SEC）。令人惊讶的是，到目前为止，还没有研究同时考虑到这两种贡献。在这里，我们通过引入光自旋发生器的新概念来实现这一目标，光自旋发生器是过渡态之间的SEC和ODI的产物。在铁磁镍中，我们的第一性原理计算表明，光自旋产生器的值越大，动态自旋矩变化越大。这个简单的发生器直接将每个晶体动量k点的随时间变化的自旋矩变化M-z(k)(t)与其固有的电子结构和磁性联系起来。这些自旋热点是光自旋发生器的直接表现，是未来研究的重点。版权所有2012作者本文采用知识共享署名3.0未移植许可协议发布。[http://dx.doi.org/10.1063/1.3693402]
Laser-induced femtosecond magnetism or femtomagnetism simultaneously relies on two distinctive contributions: (a) the optical dipole interaction (ODI) between a laser field and a magnetic system and (b) the spin expectation value change (SEC) between two transition states. Surprisingly, up to now, no study has taken both contributions into account simultaneously. Here we do so by introducing a new concept of the optical spin generator, a product of SEC and ODI between transition states. In ferromagnetic nickel, our first-principles calculation demonstrates that the larger the value of optical spin generator is, the larger the dynamic spin moment change is. This simple generator directly links the time-dependent spin moment change Delta M-z(k)(t) at every crystal-momentum k point to its intrinsic electronic structure and magnetic properties. Those hot spin spots are a direct manifestation of the optical spin generator, and should be the focus of future research. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.3693402]