Three-Dimensional Charge Density Wave and Surface Dependent Vortex Core States in a Kagome Superconductor CsV3Sb5
Three-Dimensional Charge Density Wave and Surface Dependent Vortex Core States in a Kagome Superconductor CsV3Sb5
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Kagome 超导体 CsV3Sb5 中的三维电荷密度波和表面相关涡核态
DOI：
10.1103/physrevx.11.031026
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发表时间：
2021-08-02
影响因子：
12.5
通讯作者：
Chen, X-H
中科院分区：
文献类型：
--
作者：
Liang, Zuowei;Hou, Xingyuan;Chen, X-H
基于过渡金属的可果美金属为承载各种电子不稳定性的相关拓扑相提供了通用平台。虽然超导性在层状可果美化合物中是罕见的，但它与非平凡拓扑结构的相互作用可以提供一个吸引人的空间来实现准粒子的奇异激发。本文利用扫描隧道显微镜研究了一种新发现的具有超导基态的Z（2）拓扑kagome金属CsV_3Sb_5。我们观察到的电荷调制与费米能级附近的能隙的开放。当跨越单个单元电池表面台阶边缘时，这种电荷调制的强度表现出π相移，这表明三维2 × 2 × 2电荷密度波排序。有趣的是，虽然传统的Caroli-de Gennes-Matricon束缚态在Sb表面上的超导涡旋内部观察到，但出现了一个强大的零偏置电导峰，当远离Cs 2 x 2表面上的涡旋中心时，该峰不会在很大的距离内分裂，类似于Bi 2 Te 3/NbSe 2异质结构中超导Dirac表面态产生的Majorana束缚态。我们的研究结果建立CsV 3Sb 5作为一个有前途的候选人实现异国情调的激发在汇合处的非平凡的晶格几何形状，拓扑结构和多个电子订单。
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 CsV3Sb5 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 x 2 x 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 x 2 surfaces, resembling the Majorana bound states arising from the superconducting Dirac surface states in Bi2Te3/NbSe2 heterostructures. Our findings establish CsV3Sb5 as a promising candidate for realizing exotic excitations at the confluence of nontrivial lattice geometry, topology and multiple electronic orders.