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arXiv 2402.16263cond-mat.mes-hall
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二维电子气中等离子体波的巨型共振斜散射

Giant resonant skew scattering of plasma waves in a two-dimensional electron gas

Cooper Finnigan, Dmitry K. Efimkin

AI总结:

本文研究了石墨烯中等离子体波在微磁体非均匀磁场下的散射,发现其具有巨型共振斜散射特性,且在特定频率下散射行为与拓扑绝缘体表面狄拉克电子的散射高度相似,为微米尺度直接观测单个斜散射事件提供了可能。

摘要:

杂质引起的电子斜散射是铁磁纳米结构中反常霍尔效应的主要机制之一。在拓扑绝缘体表面,由于电子动力学由自旋1/2狄拉克方程主导,该效应尤为强烈。受近期发现的流体力学与自旋1狄拉克方程之间映射关系的启发,我们考虑了石墨烯中激发的等离子体波——传播的电荷密度振荡——在相邻圆形微磁体产生的非均匀磁场下的散射。计算得到的散射振幅不仅表现出巨大的不对称性(即斜散射),而且当入射波频率与仅沿单一方向环绕微磁体的手性俘获模式频率匹配时,会发生共振增强。此外,如果入射等离子体波的频率是 Larmor 频率的数倍,其前向散射的角分布与拓扑绝缘体表面狄拉克电子在磁性杂质上散射的角分布几乎无法区分。所提装置的微米级尺度使得直接观测电子系统中以前无法触及的单个斜散射事件成为可能。

英文摘要:

Electron skew scattering by impurities is one of the major mechanisms behind the anomalous Hall effect in ferromagnetic nanostructures. It is particularly strong at the surface of topological insulators where electron dynamics is governed by the spin-1/2 Dirac equation. Motivated by recently discovered mappings between hydrodynamics and the spin-1 Dirac equation, we consider the scattering of plasma waves -- propagating charge density oscillations -- excited in graphene off a non-uniform magnetic field created by an adjacent circular micromagnet. The calculated scattering amplitude not only exhibits a giant asymmetry, or skewness, but is resonantly enhanced if the frequency of the incoming wave matches the frequency of the chiral trapped mode circulating the micromagnet in only one direction. Furthermore, if the frequency of the incoming plasma wave is a few times larger than the Larmor frequency, the angular distribution of its forward scattering is almost indistinguishable from that of a Dirac electron at the surface of a topological insulator scattering off a magnetic impurity. The micrometer scale of the proposed setup enables direct investigations of individual skew scattering events previously inaccessible in electronic systems.

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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