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arXiv 2403.05052cond-mat.mes-hall
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Rashba自旋轨道诱导的自旋织构在反常约瑟夫森效应中的作用

The role of Rashba spin-orbit induced spin textures in the anomalous Josephson effect

Ross D. Monaghan, Giuseppe C. Tettamanzi

AI总结:

该研究通过理论推导与数值验证,揭示了二维Rashba自旋轨道相互作用混合横向子带自旋产生自旋不对称,进而在外磁场下引发约瑟夫森电流反常相移的机制,且相移与磁场、自旋轨道强度均线性相关。

摘要:

本工作对反常约瑟夫森效应的底层机制开展了理论研究。我们研究的原型系统是包含二维Rashba自旋轨道相互作用的弹道二维结。本文阐明了这种二维Rashba相互作用如何混合相邻横向子带的自旋,进而在结内产生显著的自旋不对称性。当外加磁场方向同时垂直于输运轴和结的法向量时,正弦约瑟夫森电流会产生反常相移。我们首先通过推导反常相移的解析表达式,探究了单子带极限下这种自旋混合的作用。随后将分析拓展到多占据子带的系统;在该部分中,我们从微观模型出发,推导了反常相移的解析公式,表明该相移与磁场强度和自旋轨道强度均呈线性关系。最后,我们通过将所有研究结果与紧束缚模型计算的数值结果进行对比,验证了结论的正确性。

英文摘要:

This work reports the theoretical investigation into the mechanism underpinning the anomalous Josephson effect. The prototypical system we study is a ballistic two-dimensional junction containing a two-dimensional Rashba spin-orbit interaction. In this paper we demonstrate how this two-dimensional Rashba interaction mixes the spins of adjacent transverse subbands which leads to significant spin-asymmetry within the junction. Under an external magnetic field, applied perpendicular to both the axis of transport and the normal vector of the junction, the sinusoidal Josephson current can then experience an anomalous phase shift. The role of this spin mixing in the limit of a single sub-band is initially explored by deriving an analytical expression for the resulting anomalous phase shift. The analysis is then extended to systems with multiple occupied sub-bands; in this later section, starting from a microscopic model, we derive an analytic formula for the resulting anomalous phase shift indicating it is linear in both magnetic field and spin-orbit strength. We then verify and validate all findings by comparing them with numerical results evaluated by a tight-binding model.

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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