Green's function representation of spin pumping effect
Green's function representation of spin pumping effect
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自旋泵浦效应的格林函数表示
DOI：
10.1103/physrevb.94.224412
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Gen Tatara
中科院分区：
文献类型：
--
作者：
Hashimoto Kazunari;Tatara Gen;Uchiyama Chikako;Gen Tatara
本文在Keldysh绿色函数方法的基础上，研究了外加电势作用下的电流抽运，得到了用延迟和超前绿色函数表示的抽运公式。结果表明，泵浦本质上是由粒子分布的变化之前和之后的外部扰动。利用该公式研究了强交换作用下的自旋抽运效应，确定了驱动场为自旋规范场。在最低阶的磁化的旋进频率，自旋规范场作为一个恒定的电位，和该系统被证明是减少到一个静态的自旋电流产生的问题，由一个与时间无关的电位与非对角自旋分量。
In this study, current pumping by an external potential is studied on the basis of the Keldysh Green's function method, and a pumping formula written in terms of retarded and advanced Green's functions is obtained. It is shown that pumping is essentially driven by a change of particle distribution before and after an external perturbation. The formula is used to study the spin pumping effect in the case of strongexchange interaction, and the driving field is identified to be the spin gauge field. At the lowest order in the precession frequency of magnetization, the spin gauge field works as a constant potential, and the system is shown to reduce to a static problem of spin current generation by a time-independent potential with off-diagonal spin components.