论文标题
在半金属级别的Heusler Ferrimagnet Mn $ _2 $ ruga中，对全光旋转开关的第一原理见解
First-principles insights into all-optical spin switching in the half-metallic Heusler ferrimagnet Mn$_2$RuGa
论文作者
论文摘要
全光旋转开关（AOS）代表磁性存储技术的新边界 - 没有磁场的旋转操作，但其基本工作原理尚不清楚。许多AOS Ferrimagnet（例如GDFECO）是无定形的，并且使高级第一原理研究变得不可行。晶体半金属的Heusler MN $ _2 $ RUGA提供了机会。在这里，我们迄今对Mn $ _2 $ ruga的材料特性进行了全面的密度功能研究，并引入了两个概念 - 旋转锚点和光学活性位点 - 作为Ferrimagnets中AOS的两个支柱。在Mn $ _2 $ ruga中，Mn $（4A）$用作旋转锚点，其频段结构低于费米水平，并且具有强大的旋转力矩，而Mn $（4C）$是频段越过Fermi级别的光学活性站点。我们的磁光kerr谱和带结构的计算共同表明，$ 4D $和ga-ga- $ 4p $状态之间的微妙竞争负责创建这两个站点。这里找到的这两个站点不仅为Mn $ _2 $ ruga和gdfeco提供了统一图片，而且还为将来的应用打开了大门。具体来说，我们建议基于单个激光脉冲可以控制磁场的MN $ _2 $ ru $ _x $ ga $ ga。
All-optical spin switching (AOS) represents a new frontier in magnetic storage technology -- spin manipulation without a magnetic field, -- but its underlying working principle is not well understood. Many AOS ferrimagnets such as GdFeCo are amorphous and renders the high-level first-principles study unfeasible. The crystalline half-metallic Heusler Mn$_2$RuGa presents an opportunity. Here we carry out hitherto the comprehensive density functional investigation into the material properties of Mn$_2$RuGa, and introduce two concepts - the spin anchor site and the optical active site - as two pillars for AOS in ferrimagnets. In Mn$_2$RuGa, Mn$(4a)$ serves as the spin anchor site, whose band structure is below the Fermi level and has a strong spin moment, while Mn$(4c)$ is the optical active site whose band crosses the Fermi level. Our magneto-optical Kerr spectrum and band structure calculation jointly reveal that the delicate competition between the Ru-$4d$ and Ga-$4p$ states is responsible for the creation of these two sites. These two sites found here not only present a unified picture for both Mn$_2$RuGa and GdFeCo, but also open the door for the future applications. Specifically, we propose a Mn$_2$Ru$_x$Ga-based magnetic tunnel junction where a single laser pulse can control magnetoresistance.
