Dirac spin-orbit torques and charge pumping at the surface of topological insulators
Dirac spin-orbit torques and charge pumping at the surface of topological insulators
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DOI：
10.1103/physrevb.96.014408
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发表时间：
2017-07-06
影响因子：
3.7
通讯作者：
Manchon, A.
中科院分区：
文献类型：
--
作者：
Ndiaye, Papa B.;Akosa, C. A.;Manchon, A.
我们使用线性响应理论来研究拓扑绝缘体磁表面的自旋-轨道力矩的性质。我们发现，此类系统中所谓的狄拉克扭矩与拉什巴扭矩相比具有不同的对称性，并且具有作为磁化方向函数的高各向异性。特别地，当磁化位于拓扑绝缘体表面的平面中时，阻尼扭矩消失。我们还表明，Onsager倒数的自旋轨道扭矩，电荷泵，诱导增强各向异性阻尼。通过一个宏观自旋模型，我们数值模拟表明，这些功能具有重要的后果，在磁化切换。
We address the nature of spin-orbit torques at the magnetic surfaces of topological insulators using the linear-response theory. We find that the so-called Dirac torques in such systems possess a different symmetry compared to their Rashba counterpart, as well as a high anisotropy as a function of the magnetization direction. In particular, the damping torque vanishes when the magnetization lies in the plane of the topological-insulator surface. We also show that the Onsager reciprocal of the spin-orbit torque, the charge pumping, induces an enhanced anisotropic damping. Via a macrospin model, we numerically demonstrate that these features have important consequences in terms of magnetization switching.