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arXiv 0705.1432cond-mat.mes-hall
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电流驱动局域自旋的有效温度和Gilbert阻尼

Effective temperature and Gilbert damping of a current-driven localized spin

A. S. Nunez, R. A. Duine

摘要:

从一个模型,由一个半经典自旋耦合到两个引线,我们提出了一个微观推导的Langevin方程的方向的自旋。对于缓慢变化的方向,它采取随机Landau-Lifschitz-Gilbert方程的形式。我们给出了吉尔伯特阻尼参数和波动强度的表达式,包括它们与偏置电压的依赖关系。在非零偏置电压的波动和阻尼是不相关的波动耗散定理。然而,我们发现,在低频极限,它是可能的,以引入一个电压依赖的有效温度,其特点的自旋方向的波动,其运输稳态概率分布函数。

英文摘要:

Starting from a model that consists of a semiclassical spin coupled to two leads we present a microscopic derivation of the Langevin equation for the direction of the spin. For slowly-changing direction it takes on the form of the stochastic Landau-Lifschitz-Gilbert equation. We give expressions for the Gilbert damping parameter and the strength of the fluctuations, including their bias-voltage dependence. At nonzero bias-voltage the fluctuations and damping are not related by the fluctuation-dissipation theorem. We find, however, that in the low-frequency limit it is possible to introduce a voltage-dependent effective temperature that characterizes the fluctuations in the direction of the spin, and its transport-steady-state probability distribution function.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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