论文标题
揭示状态密度在控制超快自旋动力学中的作用
Uncovering the role of the density of states in controlling ultrafast spin dynamics
论文作者
论文摘要
在超快的限制下，光自旋操作的是理论上预测的光学间自旋传输（OIRT）的现象，其中激光诱导的多组分材料位点之间的电荷转移导致控制磁性。该理论的一个关键预测是，消灭效率取决于未居住的现场电荷转移状态的可用性。通过使用飞秒时间分辨率，我们采用最先进的磁光kerr效应测量值，我们通过系统比较3D Ferromagnets，FE，CO和NI及其各自的PT基于PT的合金和多层人士，探测了这一预测。我们发现（i）元素磁体中的脱氧化效率从Fe，通过CO到Ni和（II）单调增加，而多组分系统在纯元素系统上的反应效率的增益超过了纯元素对应物量表，其与空的3D少数族裔状态的数量，正如OISIST效应所预测的那样。我们通过依赖时间依赖性的密度功能理论来支持这些实验发现，我们表明，这些发现很好地捕获了实验趋势。
At the ultrafast limit of optical spin manipulation is the theoretically predicted phenomena of optical intersite spin transfer (OISTR), in which laser induced charge transfer between the sites of a multi-component material leads to control over magnetic order. A key prediction of this theory is that the demagnetization efficiency is determined by the availability of unoccupied states for intersite charge transfer. Employing state-of-the-art magneto-optical Kerr effect measurements with femtosecond time resolution, we probe this prediction via a systematic comparison of the ultrafast magnetic response between the 3d ferromagnets, Fe, Co, and Ni, and their respective Pt-based alloys and multilayers. We find that (i) the demagnetization efficiency in the elemental magnets increases monotonically from Fe, via Co to Ni and, (ii), that the gain in demagnetization efficiency of the multi-component system over the pure element counterpart scales with the number of empty 3d minority states, exactly as predicted by the OISTR effect. We support these experimental findings with ab initio time-dependent density functional theory calculations that we show to capture the experimental trends very well.
