Three-dimensional energy gap and origin of charge-density wave in kagome superconductor KV3Sb5
Three-dimensional energy gap and origin of charge-density wave in kagome superconductor KV3Sb5
复制标题
Kagome超导体KV3Sb5的三维能隙和电荷密度波起源
DOI：
10.1038/s43246-022-00255-1
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发表时间：
2022-05
影响因子：
7.8
通讯作者：
Takafumi Sato
中科院分区：
文献类型：
--
作者：
Takemi Kato;Yongkai Li;Tappei Kawakami;Min Liu;Kosuke Nakayama;Zhiwei Wang;Ayumi Moriya;Kiyohisa Tanaka;Takashi Takahashi;Yugui Yao;Takafumi Sato
Kagome晶格为探索与电子关联和能带拓扑相关的奇异量子现象提供了肥沃的土壤。最近在可果美金属KV_3Sb_5、RbV_3Sb_5和CsV_3Sb_5中发现了与电荷密度波（CDW）共存的超导电性，这表明电子有序与超导电性之间存在着有趣的纠缠。然而，CDW的微观起源，理解超导机制及其可能的拓扑性质的关键，仍然难以捉摸。在这里，我们报告的角度分辨光电子能谱的KV 3Sb 5，并证明了大量重建的费米表面在CDW状态，伴随着形成小的三维口袋。CDW带隙沿面外波矢方向呈现出沿着周期性的无畸变布里渊区，表明面内鞍点间散射对CDW机制起主导作用。利用第一性原理计算方法，通过引入逆大卫星结构畸变，得到了实验波段的色散特性。目前的结果表明，低能激发和CDW之间的直接联系，并提出了约束的微观理论的超导电性在碱金属戈薇晶格。
Kagome lattices offer a fertile ground to explore exotic quantum phenomena associated with electron correlation and band topology. The recent discovery of superconductivity coexisting with charge-density wave (CDW) in the kagome metals KV3Sb5, RbV3Sb5, and CsV3Sb5 suggests an intriguing entanglement of electronic order and superconductivity. However, the microscopic origin of CDW, a key to understanding the superconducting mechanism and its possible topological nature, remains elusive. Here, we report angle-resolved photoemission spectroscopy of KV3Sb5 and demonstrate a substantial reconstruction of Fermi surface in the CDW state that accompanies the formation of small three-dimensional pockets. The CDW gap exhibits a periodicity of undistorted Brillouin zone along the out-of-plane wave vector, signifying a dominant role of the in-plane inter-saddle-point scattering to the mechanism of CDW. The characteristics of experimental band dispersion can be captured by first-principles calculations with the inverse star-of-David structural distortion. The present result indicates a direct link between the low-energy excitations and CDW, and puts constraints on the microscopic theory of superconductivity in alkali-metal kagome lattices.
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影响因子：
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作者：
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通讯作者：
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影响因子：
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影响因子：
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作者：
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通讯作者：
Wilson, Stephen D.
DOI：
--
发表时间：
2021-05
期刊：
--
影响因子：
--
作者：
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通讯作者：
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