End States and Subgap Structure in Proximity-Coupled Chains of Magnetic Adatoms
End States and Subgap Structure in Proximity-Coupled Chains of Magnetic Adatoms
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DOI：
10.1103/physrevlett.115.197204
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发表时间：
2015-11-04
影响因子：
8.6
通讯作者：
Franke, Katharina J.
中科院分区：
文献类型：
--
作者：
Ruby, Michael;Pientka, Falko;Franke, Katharina J.
最近的实验[Nadj-Perge等人，Science 346，602（2014）]提供了超导Pb（110）表面上的铁（Fe）链中的马约拉纳零模的证据。在这里，我们研究这个系统，通过扫描隧道显微镜使用超导尖端。这种高分辨率的技术解决了丰富的subgap结构，包括零能量激发在某些链。我们比较电压反转下的数据的对称性与理论预期，并提供证据表明，推定的马约拉纳签名与以前未解决的低能量共振重叠。在马约拉纳框架内解释的数据表明，拓扑间隙小于以前提取的实验。借助于模型计算，我们还分析了更高的能量功能的subgap光谱和它们之间的关系，我们与Fe d带的高偏置峰。
A recent experiment [Nadj-Perge et al., Science 346, 602 (2014)] provides evidence for Majorana zero modes in iron (Fe) chains on the superconducting Pb(110) surface. Here, we study this system by scanning tunneling microscopy using superconducting tips. This high-resolution technique resolves a rich subgap structure, including zero-energy excitations in some chains. We compare the symmetry properties of the data under voltage reversal against theoretical expectations and provide evidence that the putative Majorana signature overlaps with a previously unresolved low-energy resonance. Interpreting the data within a Majorana framework suggests that the topological gap is smaller than previously extracted from experiment. Aided by model calculations, we also analyze higher-energy features of the subgap spectrum and their relation to high-bias peaks which we associate with the Fe d bands.