Weyl superconductor phases in a Weyl-semimetal/superconductor multilayer
Weyl superconductor phases in a Weyl-semimetal/superconductor multilayer
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DOI：
10.1103/physrevb.101.094510
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发表时间：
2019-11
影响因子：
3.7
通讯作者：
Ryota Nakai;K. Nomura
中科院分区：
文献类型：
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作者：
Ryota Nakai;K. Nomura
拓扑非平凡的超导相已经在拓扑材料中通过与常规超导体接触的邻近效应而被工程化。本文利用Kronig-Penney模型的方法，考虑由Weyl半金属层和超导层组成的多层结构，研究了Weyl半金属体电子态的超导邻近效应。由于邻近效应，两个Weyl节点解耦成四个节点的Majorana费米子，导致Weyl超导相或拓扑超导相的三维扩展。我们发现界面处费米速度和势垒的失配使Majorana结点脱离，从而使具有四个Majorana结点的Weyl超导相变为具有一半Majorana结点的Weyl超导相和具有奇数Chern数的拓扑超导相.
Topologically nontrivial superconducting phases have been engineered in topological materials by the proximity effect in contact with conventional superconductors. In this paper, by using the method of the Kronig-Penney model, we study the superconducting proximity effect in the bulk electronic states of Weyl semimetals by considering a multilayer structure consisting of Weyl-semimetal and superconductor layers. Due to the proximity effect, two Weyl nodes are decoupled into four nodes of Majorana fermions resulting in Weyl-superconductor phases or three-dimensional extension of topological-superconductor phases. We find that mismatch of the Fermi velocity and potential barriers at the interface gap out Majorana nodes, thus turn Weyl-superconductor phases with four Majorana nodes into Weyl-superconductor phases with half of Majorana nodes and topological-superconductor phases with odd integer Chern numbers.