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arXiv 2103.15078cond-mat.str-elcond-mat.supr-con
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可果美超导体KV $_3$ Sb $_5$正常态的电子关联

Electronic correlations in the normal state of kagome superconductor KV$_3$Sb$_5$

Jianzhou Zhao, Weikang Wu, Yilin Wang, Shengyuan A. Yang

摘要:

近年来,人们对新合成的kagome晶格材料$A$ V $_3$ Sb $_5$($A$ =K,Rb,Cs)的研究揭示了其有趣的物理现象,如电荷密度波和超导态。尽管进展迅速,但这些材料中的磁性和电子相关性等基本方面尚未得到清楚的理解。本文基于密度泛函理论和单格位动力学平均场论计算,研究了KV $_3$ Sb $_5$族材料在正常态下的关联电子结构和磁性.我们表明,这些材料是很好的金属弱局部相关。所得到的类保利顺磁性和局部磁矩的缺失与最近的实验结果是一致的。我们揭示了费米能级周围的带交叉形成了三组受时空反演对称性保护的节线,每组节线都携带一个量子化的$π$ Berry相位。我们的结果表明,在这些材料的局域关联强度似乎太弱,产生非常规的超导性,和非局域电子关联可能是至关重要的,在这个可果美系统。

英文摘要:

Recently, intensive studies have revealed fascinating physics, such as charge density wave and superconducting states, in the newly synthesized kagome-lattice materials $A$V$_3$Sb$_5$ ($A$=K, Rb, Cs). Despite the rapid progress, fundamental aspects like the magnetic properties and electronic correlations in these materials have not been clearly understood yet. Here, based on the density functional theory plus the single-site dynamical mean-field theory calculations, we investigate the correlated electronic structure and the magnetic properties of the KV$_3$Sb$_5$ family materials in the normal state. We show that these materials are good metals with weak local correlations. The obtained Pauli-like paramagnetism and the absence of local moments are consistent with recent experiment. We reveal that the band crossings around the Fermi level form three groups of nodal lines protected by the spacetime inversion symmetry, each carrying a quantized $π$ Berry phase. Our result suggests that the local correlation strength in these materials appears to be too weak to generate unconventional superconductivity, and non-local electronic correlation might be crucial in this kagome system.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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