论文标题
拓扑绝缘体表面状态的自旋轨道扭矩：外部自旋轨道散射对平面外磁化的影响
Spin-orbit torques from topological insulator surface states: Effect of extrinsic spin-orbit scattering on an out-of-plane magnetization
论文作者
论文摘要
不完全理解了铁磁/拓扑绝缘子（FM/TI）接口处的自旋轨道扭矩（SOT）的起源。由于表面状态在存在标量散射电位的情况下，理论压倒性地集中在Edelstein效应上。我们在这里研究表面状态的外在自旋轨道散射引起的SOT贡献，重点是平面外磁化。我们表明，旋转轨道散射带来了类似场的SOT的相当重新归一化，在外部旋转轨道参数的较大强度下超过20 $ \％$。所得的SOT表现出最大值，这是费米能，磁化和外部自旋轨道强度的函数。类似场的SOT随着障碍强度的增加而降低，而阻尼样SOT则与杂质密度无关。考虑到实验性观察，我们还确定了外部自旋轨道散射在异常大厅效应中的作用。我们的结果表明，当磁化磁化不到平面时，外在的自旋轨道散射是由埃德尔斯坦效应引起的表面SOT的重要原因。
The origins of the spin-orbit torque (SOT) at ferromagnet/topological insulator (FM/TI) interfaces are incompletely understood. Theory has overwhelmingly focussed on the Edelstein effect due to the surface states in the presence of a scalar scattering potential. We investigate here the contribution to the SOT due to extrinsic spin-orbit scattering of the surface states, focusing on the case of an out-of-plane magnetization. We show that spin-orbit scattering brings about a sizable renormalization of the field-like SOT, which exceeds 20$\%$ at larger strengths of the extrinsic spin-orbit parameter. The resulting SOT exhibits a maximum as a function of the Fermi energy, magnetization, and extrinsic spin-orbit strength. The field-like SOT decreases with increasing disorder strength while the damping-like SOT is independent of the impurity density. With experimental observation in mind we also determine the role of extrinsic spin-orbit scattering on the anomalous Hall effect. Our results suggest extrinsic spin-orbit scattering is a significant contributor to the surface SOT stemming from the Edelstein effect when the magnetization is out of the plane.
