Recently discovered $Z_2$ topological kagome metals $A{\mathrm{V}}_3{\mathrm{Sb}}_5$ ($A=\mathrm{K}$, Rb, and Cs) exhibit charge-density-wave (CDW) phases and novel superconducting paring states providing a versatile platform for studying the interplay between electron correlation and quantum orders. Here we directly visualize CDW-induced bands renormalization and energy gaps in ${\mathrm{RbV}}_3{\mathrm{Sb}}_5$ using angle-resolved photoemission spectroscopy pointing to the key role of tuning van Hove singularities to the Fermi energy in mechanisms of ordering phases. Near the CDW transition temperature, the bands around the Brillouin zone (BZ) boundary are shifted to high-binding energy, forming an $\mathsf{M}$-shaped band with singularities near the Fermi energy. The Fermi surfaces are partially gapped, and the electronic states on the residual ones should be possibly dedicated to the superconductivity. Our findings are significant in understanding CDW formation and its associated superconductivity.

中文翻译：

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Kagome超导体RbV3Sb5中的电荷密度波诱导带重整化和能隙

最近发现 $Z_2$ 拓扑戈美金属 $\mathrm{一种}{\mathrm{伏}}_3{锑}_5$ ($\mathrm{一种}=\mathrm{钾}$、Rb 和 Cs) 表现出电荷密度波 (CDW) 相位和新型超导配对状态，为研究电子相关性和量子阶数之间的相互作用提供了一个通用平台。在这里，我们直接可视化 CDW 诱导的带重整化和能隙${\mathrm{比值}}_3{锑}_5$使用角分辨光电子能谱法指出在有序相的机制中将范霍夫奇点调谐到费米能量的关键作用。在 CDW 转变温度附近，布里渊区 (BZ) 边界周围的能带转移到高结合能，形成$\mathsf{米}$带奇点在费米能量附近。费米表面部分有间隙，剩余表面上的电子态可能专用于超导性。我们的发现对于理解 CDW 的形成及其相关的超导性具有重要意义。