论文标题

封装的双层石墨烯中的Majorana绑定状态

Majorana bound states in encapsulated bilayer graphene

论文作者

Peñaranda, Fernando, Aguado, Ramón, Prada, Elsa, San-Jose, Pablo

论文摘要

寻找强大的拓扑超导性和Majoraana绑定状态继续进行,探索一维(1D)系统,例如半导体纳米线和二维(2D)平台。在这项工作中,我们研究了一种基于封装在过渡金属二分法中的石墨烯双层的2D方法,该方法与以前涉及石墨烯中量子霍尔制度的建议不同,需要较弱的磁场,并且不依赖相互作用。封装在石墨烯双层上诱导了强的自旋轨道耦合,从而打开了巨大的间隙,并稳定了螺旋边缘状态的脆弱对。我们表明,当受到面板内采地时,扶手椅边缘可以通过与常规的超导体横向接触,将扶手椅边缘转换为P波一维拓扑超导体。我们证明了Majorana结合状态(MBS)在晶体学上完美片段的样品角,属于D或BDI对称类,具体取决于参数。我们计算相图,MBS对缺陷的弹性以及它们在约瑟夫森结几何形状中的4 $π$周期效应的表现,所有这些都表明在实验范围内存在拓扑阶段。

The search for robust topological superconductivity and Majorana bound states continues, exploring both one-dimensional (1D) systems such as semiconducting nanowires and two-dimensional (2D) platforms. In this work we study a 2D approach based on graphene bilayers encapsulated in transition metal dichalcogenides that, unlike previous proposals involving the Quantum Hall regime in graphene, requires weaker magnetic fields and does not rely on interactions. The encapsulation induces strong spin-orbit coupling on the graphene bilayer, which opens a sizeable gap and stabilizes fragile pairs of helical edge states. We show that, when subject to an in-plane Zeeman field, armchair edges can be transformed into p-wave one-dimensional topological superconductors by contacting them laterally with conventional superconductors. We demonstrate the emergence of Majorana bound states (MBSs) at the sample corners of crystallographically perfect flakes, belonging either to the D or the BDI symmetry classes depending on parameters. We compute the phase diagram, the resilience of MBSs against imperfections, and their manifestation as a 4$π$-periodic effect in Josephson junction geometries, all suggesting the existence of a topological phase within experimental reach.

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