压力诱导的kagome金属AV3Sb5 (A = K, Rb, Cs)中的非常规电荷密度波态
Pressure-induced unconventional charge-density-wave states in kagome metal AV3Sb5 (A = K, Rb, Cs)
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China（中国科学技术大学微观尺度物理国家研究中心）
- Department of Physics, University of Science and Technology of China（中国科学技术大学物理系）
- School of Physics, Hefei University of Technology（合肥工业大学物理学院）
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University（南京大学先进微结构协同创新中心）
- Hefei National Laboratory, University of Science and Technology of China（中国科学技术大学合肥国家实验室）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
本研究通过NMR实验发现，kagome金属AV3Sb5在压力下普遍存在非公度三Q电荷密度波，该非常规CDW由van Hove奇点驱动的电子涨落调控，且不强烈抑制超导温度。
中文摘要 AI 辅助
自从电荷密度波（CDW）和超导电性被发现以来，kagome金属AV3Sb5（A = K, Rb, Cs）为探索新奇的多体量子现象提供了新的平台。在CsV3Sb5中，在中等压力下观察到了具有公度波矢q = 3/8的条状CDW，这导致了压力-温度相图中奇特的超导双穹顶行为。先前的密度泛函理论（DFT）计算表明，压力诱导的条状CDW超出了常规的声子软化机制，暗示了电子关联的非平凡作用。然而，对压力诱导的非常规CDW的深入理解仍然难以捉摸。在此，我们对KV3Sb5和RbV3Sb5进行了压力依赖的51V核磁共振（NMR）测量。尽管加压的KV3Sb5和RbV3Sb5中不存在超导双穹顶行为，但在两种材料中，NMR谱均识别出一个压力诱导的CDW相，该相归因于可能的非公度三Q CDW，表明超出DFT计算的压力诱导非常规CDW是kagome金属AV3Sb5的普遍特征。与条状CDW相反，压力诱导的非公度三Q CDW并未强烈抑制超导转变温度（Tc），而是在压力依赖的超导相图的中间压力区域与近乎平台的行为相吻合。此外，通过系统分析AV3Sb5中Knight位移与核自旋-晶格弛豫率之间的Korringa关系，揭示了由van Hove奇点（vHSs）驱动的电子涨落是压力诱导非常规CDW的有效调控手段。最后，我们的发现强调了压力诱导的非常规CDW是kagome金属AV3Sb5中一种新颖的关联量子态。
英文摘要
Since the discovery of charge density wave (CDW) and superconductivity, kagome metal AV3Sb5 (A = K, Rb, Cs) provides a new platform for exploring novel many-body quantum phenomena. In CsV3Sb5, a stripe-like CDW with commensurate wave vector q = 3/8 was observed under moderate pressures, which leads to a peculiar superconducting double-dome behavior in pressure-dependent phase diagram. Previous density functional theory (DFT) calculations indicate that the pressure-induced stripe-like CDW is beyond conventional phonon softening scenario, suggesting a nontrivial role of electronic correlations. However, an in-depth understanding for the pressure-induced unconventional CDW remains elusive. Here, we performed pressure-dependent 51V nuclear magnetic resonance (NMR) measurements on KV3Sb5 and RbV3Sb5. Although the superconducting double-dome behavior is absent in pressurized KV3Sb5 and RbV3Sb5, a pressure-induced CDW phase, ascribed to a possible incommensurate triple-Q CDW, is identified by NMR spectra in both materials, indicating that the pressure-induced unconventional CDW beyond DFT calculations is a common feature for kagome metal AV3Sb5. In contrast to the stripe-like CDW, the pressure-induced incommensurate triple-Q CDW does not strongly suppress the superconducting temperature (Tc) but coincide with an almost plateau behavior at intermediate pressure regime in the pressure-dependent superconducting phase diagram. Furthermore, by systematically analyzing the Korringa relation between Knight shift and nuclear spin-lattice relaxation rate in AV3Sb5, van Hove singularities (vHSs) driven electronic fluctuations are revealed as an effective knob for the pressure-induced unconventional CDW. Finally, our present findings underscore the pressure-induced unconventional CDW as a novel correlated quantum state in kagome metal AV3Sb5.
