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arXiv 2004.10556cond-mat.mes-hall
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分子Andreev干涉仪中的量子干涉和非平衡Josephson电流

Quantum interference and nonequilibrium Josephson current in molecular Andreev interferometers

Noel L. Plaszkó, Peter Rakyta, József Cserti, Andor Kormányos, Colin J. Lambert

摘要:

研究了非平衡条件下基于多环芳烃的三端Andreev干涉仪的量子干涉效应。Andreev干涉仪由耦合到两个超导和一个正常导电端子的PAH组成。我们计算了在正常引线中测量的电流以及在非平衡条件下超导端子之间的电流。我们表明,无论是QI中产生的PAH核心和施加到正常接触的偏置电压有一个基本的影响与Andreev束缚态(ABS)的电荷分布。QI可以导致正常电流对超导相位差的特殊依赖性,这在介观Andreev干涉仪的早期研究中没有观察到。我们解释我们的结果由诱导的电子和空穴类准粒子的空间分布的不对称性。在正常引线上施加足够大的偏置电压时,在中心PAH核中诱导的非平衡电荷占据可以导致超电流的电流-相位关系中的$π$转变。类电子和类空穴准粒子空间分布的不对称性可能被用来分裂库珀对,从而在四个终端设置中产生纠缠电子。

英文摘要:

We study the quantum interference (QI) effects in three-terminal Andreev interferometers based on polyaromatic hydrocarbons (PAH's) under non-equilibrium conditions. The Andreev interferometer consists of a PAH coupled to two superconducting and one normal conducting terminals. We calculate the current measured in the normal lead as well as the current between the superconducting terminals under non-equilibrium conditions. We show that both the QI arising in the PAH cores and the bias voltage applied to a normal contact have a fundamental effect on the charge distribution associated with the Andreev Bound States (ABS's). QI can lead to a peculiar dependence of the normal current on the superconducting phase difference that was not observed in earlier studies of mesoscopic Andreev interferometers. We explain our results by an induced asymmetry in the spatial distribution of the electron- and hole-like quasiparticles. The non-equilibrium charge occupation induced in the central PAH core can result in a $π$ transition in the current-phase relation of the supercurrent for large enough applied bias voltage on the normal lead. The asymmetry in the spatial distribution of the electron- and hole-like quasiparticles might be used to split Cooper pairs and hence to produce entangled electrons in four terminal setups.

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