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arXiv 2007.13579cond-mat.mes-hall
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拓扑绝缘体双层膜中Majorana角态的Kramers对

Kramers pairs of Majorana corner states in a topological insulator bilayer

Katharina Laubscher, Danial Chughtai, Daniel Loss, Jelena Klinovaja

摘要:

我们考虑了一个由两个隧道耦合的二维拓扑绝缘体组成的系统,该绝缘体被一个顶部和底部超导体近似,它们之间的相位差为$π$。我们表明,该系统具有时间反演不变的二阶拓扑超导相,其特征在于在所有四个角的矩形样品的Kramers对马约拉纳角状态的存在。此外,我们研究了弱时间反演对称性破缺微扰的影响,并表明,在平面塞曼场导致一个更丰富的相图,表现出两个非等价的阶段,每个角落有两个马约拉纳角状态,以及一个中间阶段,每个角落只有一个马约拉纳角状态。我们从描述我们系统的连续模型中解析得出我们的结果。此外,我们还提供了独立的数值确认所产生的阶段,使用离散化的晶格表示的模型,这使我们能够证明的鲁棒性的拓扑相位和马约拉纳角状态对参数变化和潜在的混乱。

英文摘要:

We consider a system consisting of two tunnel-coupled two-dimensional topological insulators proximitized by a top and bottom superconductor with a phase difference of $π$ between them. We show that this system exhibits a time-reversal invariant second-order topological superconducting phase characterized by the presence of a Kramers pair of Majorana corner states at all four corners of a rectangular sample. We furthermore investigate the effect of a weak time-reversal symmetry breaking perturbation and show that an in-plane Zeeman field leads to an even richer phase diagram exhibiting two nonequivalent phases with two Majorana corner states per corner as well as an intermediate phase with only one Majorana corner state per corner. We derive our results analytically from continuum models describing our system. In addition, we also provide independent numerical confirmation of the resulting phases using discretized lattice representations of the models, which allows us to demonstrate the robustness of the topological phases and the Majorana corner states against parameter variations and potential 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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