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arXiv 2109.10089cond-mat.mes-hallcond-mat.str-el
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耦合到Kane-Mele模型螺旋边态的自旋的实时动力学控制

Controlling the real-time dynamics of a spin coupled to the helical edge states of the Kane-Mele model

Robin Quade, Michael Potthoff

摘要:

通过求解自旋和电子系统的耦合微观运动方程组,数值研究了在拓扑非平凡相中耦合到Kane-Mele模型边缘位置的经典自旋局域交换的含时态.由于耗散边界条件,除了感兴趣的锯齿形边缘之外,所有的边界条件都适用于长时间限制的动态。我们研究的手段来控制状态的自旋通过运输的自旋极化云通过螺旋边缘状态。该云是在远边缘位置使用局部磁场注入电子自旋密度形成的,并通过突然关闭注入场而释放。这个基本的过程,包括自旋注入,自旋极化云的传播,以及云从经典自旋的散射,可以用来以受控的方式操纵自旋状态。我们发现,一个单一的基本过程的效果可以恢复到一个较高的程度与后续的过程。此外,我们表明,通过串联几个基本的注入-传播-散射过程,自旋状态可以完全切换,可以实现完全逆转。

英文摘要:

The time-dependent state of a classical spin locally exchange coupled to an edge site of a Kane-Mele model in the topologically non-trivial phase is studied numerically by solving the full set of coupled microscopic equations of motion for the spin and the electron system. Dynamics in the long-time limit is accessible thanks to dissipative boundary conditions, applied to all but the zigzag edge of interest. We study means to control the state of the spin via transport of a spin-polarization cloud through the helical edge states. The cloud is formed at a distant edge site using a local magnetic field to inject an electron spin density and released by suddenly switching off the injection field. This basic process, consisting of spin injection, propagation of the spin-polarization cloud, and scattering of the cloud from the classical spin, can be used to steer the spin state in a controlled way. We find that the effect of a single basic process can be reverted to a high degree with a subsequent process. Furthermore, we show that by concatenating several basic injection-propagation-scattering processes, the spin state can be switched completely and that a full reversal can be achieved.

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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