论文标题
铁磁异质结构中自旋轨道扭矩的微观起源：第一原理方法
Microscopic Origin of Spin-Orbit Torque in Ferromagnetic Heterostructures: A First Principles Approach
论文作者
论文摘要
我们提出了一个基于{\ it i i}的理论框架，该框架阐明了在正常金属（NM）/Ferromagnet（FM）异质结构中旋转轨道扭矩（SOT）的起源。 SOT分解为两个贡献，即{\ it spin-hall}和{\ it spin-orbital}组件。我们发现{\ it（i）}磁场样（FL）SOT由自旋 - 轨道分量支配，并且{\ it（ii）}两个组件都有助于阻尼样扭矩，在厚Pt膜的极限中具有相当的大小。自旋轨道成分对DL-SOT的贡献仅适用于具有强大SOC耦合强度的NMS。我们证明，FL-SOT可以用非平衡性自旋分辨轨道矩积累来表达。该计算表明，PT/CO Bilayers中FL-SOT的氧诱导的氧诱导的标志反转是由于大多数旋转轨道矩累积在界面NM原子上的显着降低所致。
We present an {\it ab initio}-based theoretical framework which elucidates the origin of the spin-orbit torque (SOT) in Normal-Metal(NM)/Ferromagnet(FM) heterostructures. The SOT is decomposed into two contributions, namely, {\it spin-Hall} and the {\it spin-orbital} components. We find that {\it (i)} the Field-Like (FL) SOT is dominated by the spin-orbital component and {\it (ii)} both components contribute to the damping-like torque with comparable magnitude in the limit of thick Pt film. The contribution of the spin-orbital component to the DL-SOT is present only for NMs with strong SOC coupling strength. We demonstrate that the FL-SOT can be expressed in terms of the non-equilibrium spin-resolved orbital moment accumulation. The calculations reveal that the experimentally reported oxygen-induced sign-reversal of the FL-SOT in Pt/Co bilayers is due to the significant reduction of the majority-spin orbital moment accumulation on the interfacial NM atoms.
