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arXiv 0909.1892cond-mat.mes-hall
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线性自旋轨道相互作用的动态自旋-霍尔效应和驱动自旋螺旋

Dynamic spin-Hall effect and driven spin helix for linear spin-orbit interactions

Mathias Duckheim, Dmitrii L. Maslov, Daniel Loss

摘要:

我们推导出在有限的,无序的二维半导体沟道的电诱导自旋积累的边界条件。而对于直流电场,这些边界条件选择空间恒定的自旋轮廓,相当于消失的自旋霍尔效应,我们表明,在一个非零的交流自旋霍尔效应,即,即使对于线性固有自旋轨道相互作用,它也产生空间非均匀的面外极化。分析[001]和[110]生长量子阱中的不同几何结构,我们发现,尽管这种面外极化通常被限制在距离沟道边缘的几个自旋轨道长度内,但也有可能产生在整个沟道上延伸的空间振荡自旋分布。后者是由于在通道的横向方向上的驱动自旋螺旋模式的激发。我们表明,虽然有限的频率抑制这种模式,它可以被放大的磁场调谐到谐振频率的电场。在这种情况下,在相同强度的Rashba和Dresselhaus SOI的有限尺寸效应导致该螺旋模式的幅度的增强。本文讨论了自旋流与边界条件的关系。

英文摘要:

We derive boundary conditions for the electrically induced spin accumulation in a finite, disordered 2D semiconductor channel. While for DC electric fields these boundary conditions select spatially constant spin profiles equivalent to a vanishing spin-Hall effect, we show that an in-plane ac electric field results in a non-zero ac spin-Hall effect, i.e., it generates a spatially non-uniform out-of-plane polarization even for linear intrinsic spin-orbit interactions. Analyzing different geometries in [001] and [110]-grown quantum wells, we find that although this out-of-plane polarization is typically confined to within a few spin-orbit lengths from the channel edges, it is also possible to generate spatially oscillating spin profiles which extend over the whole channel. The latter is due to the excitation of a driven spin-helix mode in the transverse direction of the channel. We show that while finite frequencies suppress this mode, it can be amplified by a magnetic field tuned to resonance with the frequency of the electric field. In this case, finite size effects at equal strengths of Rashba- and Dresselhaus SOI lead to an enhancement of the magnitude of this helix mode. We comment on the relation between spin currents and boundary conditions.

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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