论文标题
铁pnictides中的边界刺激性拓扑高-T $ _C $超导性
Boundary-obstructed topological high-T$_c$ superconductivity in iron pnictides
论文作者
论文摘要
非平凡的拓扑结构和非常规配对是当代搜索和分析超导材料和异质结构化合物的两个核心指导原则。以前,拓扑超导体主要是由于受到内在或外部超导接近效应的拓扑非平凡带造成的。在这里,我们提出了一类新的拓扑超导体,它们是由非常规配对引起的。它们表现出边界刺激的高阶拓扑特征,并取决于其维度,具有前所未有的稳健的主要结合状态或受手性对称性保护的铰链模式。我们预测铁pnictides的112家户主,例如Ca $ _ {1-x} $ la $ _x $ feas $ _2 $,是我们建议的高度适合的材料候选者,可以通过边缘光谱测试。由于边界刺激性,112个pnictides的拓扑非平地特征并没有在没有边界的情况下进行仅大量的圆环带分析,因此已经避免了先前的研究。我们的建议不仅为高温超导体的高度稳定的主要模式开设了一个新的舞台,而且还为铁pnictides中的延长S波秩序提供了吸烟枪证据。
Non-trivial topology and unconventional pairing are two central guiding principles in the contemporary search for and analysis of superconducting materials and heterostructure compounds. Previously, a topological superconductor has been predominantly conceived to result from a topologically non-trivial band subject to intrinsic or external superconducting proximity effect. Here, we propose a new class of topological superconductors which are uniquely induced by unconventional pairing. They exhibit a boundary-obstructed higher-order topological character and, depending on their dimensionality, feature unprecedently robust Majorana bound states or hinge modes protected by chiral symmetry. We predict the 112-family of iron pnictides, such as Ca$_{1-x}$La$_x$FeAs$_2$, to be a highly suited material candidate for our proposal, which can be tested by edge spectroscopy. Because of the boundary-obstruction, the topologically non-trivial feature of the 112 pnictides does not reveal itself for a bulk-only torus band analysis without boundaries, and as such had evaded previous investigations. Our proposal not only opens a new arena for highly stable Majorana modes in high-temperature superconductors, but also provides the smoking gun evidence for extended s-wave order in the iron pnictides.