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arXiv 1008.0629cond-mat.supr-concond-mat.str-el
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在多带半导体纳米线中寻找Majorana费米子

Search for Majorana fermions in multiband semiconducting nanowires

Roman M. Lutchyn, Tudor Stanescu, S. Das Sarma

摘要:

我们研究多能带半导体纳米线与s波超导体的邻近耦合。我们表明,当奇数的子带被占用的系统实现非平凡的拓扑状态支持本地化的马约拉纳模式在两端。我们研究了该系统的拓扑量子相变,并解析计算了作为化学势和磁场函数的相图。我们的主要发现是,多频带占用不仅解除了严格的一维约束,但也允许有更高的载流子密度的纳米线,这样的多子带纳米线更适合于观察马约拉纳粒子。我们研究的鲁棒性的拓扑相位,包括短期和长期的障碍的影响。我们表明,在强带间混合的限制,有一个最佳的制度在相图(“甜蜜点”)的拓扑状态在很大程度上是不敏感的无序的存在。

英文摘要:

We study multiband semiconducting nanowires proximity-coupled with an s-wave superconductor. We show that when odd number of subbands are occupied the system realizes non-trivial topological state supporting Majorana modes localized at the ends. We study the topological quantum phase transition in this system and analytically calculate the phase diagram as a function of the chemical potential and magnetic field. Our key finding is that multiband occupancy not only lifts the stringent constraint of one-dimensionality but also allows to have higher carrier density in the nanowire and as such multisubband nanowires are better-suited for observing the Majorana particle. We study the robustness of the topological phase by including the effects of the short- and long-range disorder. We show that in the limit of strong interband mixing there is an optimal regime in the phase diagram ("sweet spot") where the topological state is to a large extent insensitive to the presence of disorder.

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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