论文标题
铁 - /铁磁性绝缘体的有限频旋转电导|正常水平界面
Finite-frequency spin conductance of a ferro-/ferrimagnetic-insulator|normal-metal interface
论文作者
论文摘要
铁磁绝缘子和正常金属之间的界面可以支撑自旋电流极化的共线，并垂直于磁化方向。垂直于磁化方向的角动量的流动（“横向”旋转电流）通过自旋扭矩和自旋泵送发生。与磁化（“纵向”自旋电流）的角动量共线的流动需要激发镁。在本文中，我们扩展了纵向自旋运输的现有理论[Bender and Tserkovnyak，Phys。 Rev. B 91，140402（R）（2015）]在两个方向上的零频率弱耦合极限中：我们非扰动（但在低频极限）和有限频率（但在低接口透明度的极限下）计算纵向旋转电导率（但在低频极限下）。对于范式的自旋材料系统yig | pt，我们发现非扰动效应会导致纵向自旋电导。 40％比扰动极限小，而有限频率校正仅在低温<100 k的情况下相关，而只有少量的磁通模式被热占据。
The interface between a ferro-/ferrimagnetic insulator and a normal metal can support spin currents polarized collinear with and perpendicular to the magnetization direction. The flow of angular momentum perpendicular to the magnetization direction ("transverse" spin current) takes place via spin torque and spin pumping. The flow of angular momentum collinear with the magnetization ("longitudinal" spin current) requires the excitation of magnons. In this article we extend the existing theory of longitudinal spin transport [Bender and Tserkovnyak, Phys. Rev. B 91, 140402(R) (2015)] in the zero-frequency weak-coupling limit in two directions: We calculate the longitudinal spin conductance non-perturbatively (but in the low-frequency limit) and at finite frequency (but in the limit of low interface transparency). For the paradigmatic spintronic material system YIG|Pt, we find that non-perturbative effects lead to a longitudinal spin conductance that is ca. 40% smaller than the perturbative limit, whereas finite-frequency corrections are relevant at low temperatures < 100 K only, when only few magnon modes are thermally occupied.
