Superconducting topological crystalline insulators (TCIs) have been proposed to be a new type of topological superconductor where multiple Majorana zero modes may coexist under the protection of lattice symmetries. The bulk superconductivity of TCIs has been realized, but it is quite challenging to detect the superconductivity of topological surface states inside their bulk superconducting gaps. Here, we report high-resolution scanning tunneling spectroscopy measurements on lateral ${\mathrm{Sn}}_{1-x}{\mathrm{Pb}}_x\mathrm{Te}\text{−}\mathrm{Pb}$ heterostructures using superconducting tips. Both the bulk superconducting gap and the multiple in-gap states with energy differences of $\sim 0.3\mathrm{meV}$ can be clearly resolved on TCI ${\mathrm{Sn}}_{1-x}{\mathrm{Pb}}_x\mathrm{Te}$ at 0.38 K. Quasiparticle interference measurements further confirm the in-gap states are gapless. Our work demonstrates that the unique topological superconductivity of a TCI can be directly distinguished in the density of states, which helps to further investigate the multiple Dirac and Majorana fermions inside the superconducting gap.

中文翻译：

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拓扑表面态在超导拓扑晶体绝缘子异质结构中诱导的多个能隙状态Sn1-xPbxTe-Pb

已经提出超导拓扑晶体绝缘体（TCI）是一种新型的拓扑超导体，其中在晶格对称性的保护下，多个Majorana零模式可以共存。TCI的体超导性已经实现，但要检测其体超导间隙内部的拓扑表面态的超导性是非常具有挑战性的。在这里，我们报告了在横向上的高分辨率扫描隧道光谱测量${锡}_{\mathrm{1个}-X}{\mathrm{铅含量}}_X特\text{-}\mathrm{铅含量}$使用超导尖端的异质结构。体超导能隙和能隙为$〜0.3\mathrm{病毒}$ 可以在TCI上得到明确解决 ${锡}_{\mathrm{1个}-X}{\mathrm{铅含量}}_X特$在0.38 K时。准粒子干涉测量进一步证实了间隙内状态是无间隙的。我们的工作表明，TCI独特的拓扑超导性可以在状态密度中直接区分，这有助于进一步研究超导间隙中的多个狄拉克和马约拉纳费米子。