The transition-metal-based kagome metals provide a versatile platform for correlated topological phases hosting various electronic instabilities. While superconductivity is rare in layered kagome compounds, its interplay with nontrivial topology could offer an engaging space to realize exotic excitations of quasiparticles. Here, we use scanning tunneling microscopy to study a newly discovered $Z_2$ topological kagome metal ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ with a superconducting ground state. We observe charge modulation associated with the opening of an energy gap near the Fermi level. When across single-unit-cell surface step edges, the intensity of this charge modulation exhibits a $\pi$-phase shift, suggesting a three-dimensional $2\times 2\times 2$ charge density wave ordering. Interestingly, while conventional Caroli–de Gennes–Matricon bound states are observed inside the superconducting vortex on the Sb surfaces, a robust zero-bias conductance peak emerges that does not split in a large distance when moving away from the vortex center on the Cs $2\times 2$ surfaces, resembling the Majorana bound states arising from the superconducting Dirac surface states in ${\mathrm{Bi}}_2{\mathrm{Te}}_3/{\mathrm{NbSe}}_2$ heterostructures. Our findings establish ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ as a promising candidate for realizing exotic excitations at the confluence of nontrivial lattice geometry, topology and multiple electronic orders.

中文翻译：

---

Kagome 超导体 CsV3Sb5 中的三维电荷密度波和表面相关涡核状态

基于过渡金属的 Kagome 金属为具有各种电子不稳定性的相关拓扑相提供了通用平台。虽然超导性在分层 kagome 化合物中很少见，但它与非平凡拓扑结构的相互作用可以提供一个引人入胜的空间来实现准粒子的奇异激发。在这里，我们使用扫描隧道显微镜来研究新发现的$Z_2$ 拓扑戈美金属 ${\mathrm{电压}}_3{锑}_5$具有超导基态。我们观察到与费米能级附近的能隙打开相关的电荷调制。当跨越单个单元表面台阶边缘时，这种电荷调制的强度表现出$\pi$- 相移，表明一个三维 $2\times 2\times 2$电荷密度波排序。有趣的是，虽然在 Sb 表面的超导涡流内观察到了传统的 Caroli-de Gennes-Matricon 束缚态，但出现了一个强大的零偏置电导峰，当远离 Cs 上的涡流中心时，它不会分裂很远$2\times 2$ 表面，类似于由超导狄拉克表面态产生的马约拉纳束缚态 ${双}_2{特}_3/{\mathrm{铌硒}}_2$异质结构。我们的研究结果表明${\mathrm{电压}}_3{锑}_5$ 作为在非平凡晶格几何、拓扑和多个电子顺序的汇合处实现奇异激发的有希望的候选者。