Nontopological zero-bias peaks in full-shell nanowires induced by flux-tunable Andreev states
Nontopological zero-bias peaks in full-shell nanowires induced by flux-tunable Andreev states
复制标题
DOI：
10.1126/science.abf1513
复制
发表时间：
2021-07-02
期刊：
影响因子：
56.9
通讯作者：
Katsaros, Georgic
中科院分区：
文献类型：
--
作者：
Valentini, Marco;Penaranda, Fernando;Katsaros, Georgic
已提出一种完全被超导壳包裹的半导体纳米线作为在小磁场下获得马约拉纳模式的平台。在这项研究中，我们证明了这种结构中亚带隙态的出现实际上是由隧道光谱测量中的结区域决定的，而不是全壳纳米线本身。短隧道区域永远不会显示亚带隙状态，而较长的结总是显示。这可以从结点中形成的量子点和 Yu-Shiba-Rusinov 体系中的安德烈夫能级来理解。通过塞曼和利特尔帕克斯效应，安德烈夫能级的复杂磁场依赖性可能会产生强大的零偏置峰值特征，这些特征很容易被误解为源自马约拉纳零模式，但与拓扑超导性无关。
A semiconducting nanowire fully wrapped by a superconducting shell has been proposed as a platform for obtaining Majorana modes at small magnetic fields. In this study, we demonstrate that the appearance of subgap states in such structures is actually governed by the junction region in tunneling spectroscopy measurements and not the full-shell nanowire itself. Short tunneling regions never show subgap states, whereas longer junctions always do. This can be understood in terms of quantum dots forming in the junction and hosting Andreev levels in the Yu-Shiba-Rusinov regime. The intricate magnetic field dependence of the Andreev levels, through both the Zeeman and Little-Parks effects, may result in robust zero-bias peaks-features that could be easily misinterpreted as originating from Majorana zero modes but are unrelated to topological superconductivity.