Joseph Henry Laboratories and Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Institute for Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
Science. 2019 Jun 28;364(6447):1255-1259. doi: 10.1126/science.aax1444. Epub 2019 Jun 13.
Superconducting proximity pairing in helical edge modes, such as those of topological insulators, is predicted to provide a unique platform for realizing Majorana zero modes (MZMs). We used scanning tunneling microscopy measurements to probe the influence of proximity-induced superconductivity and magnetism on the helical hinge states of bismuth(111) films grown on a superconducting niobium substrate and decorated with magnetic iron clusters. Consistent with model calculations, our measurements revealed the emergence of a localized MZM at the interface between the superconducting helical edge channel and the iron clusters, with a strong magnetization component along the edge. Our experiments also resolve the MZM's spin signature, which distinguishes it from trivial in-gap states that may accidentally occur at zero energy in a superconductor.
螺旋边缘模式中的超导近邻配对，如拓扑绝缘体中的那种，预计将为实现马约拉纳零模（MZM）提供一个独特的平台。我们使用扫描隧道显微镜测量来探测近邻诱导超导性和磁性对生长在超导铌衬底上并被磁性铁簇装饰的铋（111）薄膜的螺旋铰链状态的影响。与模型计算一致，我们的测量结果显示出超导螺旋边缘通道和铁簇之间界面处局域 MZM 的出现，其边缘具有强烈的磁化分量。我们的实验还解决了 MZM 的自旋特征，将其与超导体内可能意外出现在零能量处的平凡带隙态区分开来。
