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arXiv 2104.12441cond-mat.mes-hallcond-mat.supr-con
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三维高阶拓扑超导体系

Hierarchy of higher-order topological superconductors in three dimensions

Arnob Kumar Ghosh, Tanay Nag, Arijit Saha

摘要:

在对二维高阶拓扑超导体(HOTSCs)中的Majorana角模(MCMs)进行了大量研究之后,我们提出了一个基于三维拓扑绝缘体的简单费米子模型,该模型用$s$波超导体近似,在适当的Wilson-Dirac微扰下实现了Majorana铰链模(MHM)和MCMs.我们有趣地发现,二阶拓扑超导体,托管MHMs,出现在第一类微扰的阈值以上,而三阶拓扑超导相,支持MCMs,立即出现结合第二类的无穷小微扰。因此,HOTSC相的层次结构可以在单个三维模型中实现。此外,发现体磁场的应用有助于操纵MHM的数量,使MCM的数量不变。我们通过诉诸低能模型来分析理解上述数值结果。我们进一步表征这些拓扑相位与一个独特的结构的Wannier谱。从实际的角度来看,我们表现出这些高阶模式的量化传输签名。最后,我们构建Floquet工程产生的层次结构的HOTSC阶段踢相同的扰动,认为在他们的静态对应。

英文摘要:

After exploring much on two-dimensional higher-order topological superconductors (HOTSCs) hosting Majorana corner modes (MCMs) only, we propose a simple fermionic model based on a three-dimensional topological insulator proximized with $s$-wave superconductor to realize Majorana hinge modes (MHMs) followed by MCMs under the application of appropriate Wilson-Dirac perturbations. We interestingly find that the second-order topological superconductor, hosting MHMs, appears above a threshold value of the first type perturbation while the third-order topological superconducting phase, supporting MCMs, immediately arises incorporating infinitesimal perturbation of the second kind. Thus, a hierarchy of HOTSC phases can be realized in a single three-dimensional model. Additionally, the application of bulk magnetic field is found to be instrumental in manipulating the number of MHMs, leaving the number for MCMs unaltered. We analytically understand these above-mentioned numerical findings by resorting to the low energy model. We further characterize these topological phases with a distinct structure of the Wannier spectra. From the practical point of view, we manifest quantized transport signatures of these higher-order modes. Finally, we construct Floquet engineering to generate the hierarchy of HOTSC phases by kicking the same perturbations as considered in their static counterpart.

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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