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arXiv 2105.04546cond-mat.str-elcond-mat.supr-con
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铜氧化物及相关高温超导体中的高阶Van Hove奇性

High-order Van Hove singularities in cuprates and related high-Tc superconductors

Robert S. Markiewicz, Bahadur Singh, Christopher Lane, Arun Bansil

摘要:

与鞍点或能量色散极值相关的二维范霍夫奇点通常在态密度上表现出对数发散。然而,最近的研究发现,起源于高阶鞍点的VHS具有快于对数的发散,这可以放大电子相关效应,并在二维材料中产生奇异态,如超金属。在这里,我们报告的存在下的“高阶”VHS的铜酸盐和相关的高Tc超导体,并表明,在其光谱的异常分歧是由系统的电子维数低于晶格的维数。VHS的顺序被发现与超导Tc,从而具有更高的顺序VHS显示更高的Tc的材料。我们进一步表明,在电子光谱中的正常和高阶VHS的存在下,可以提供一个简单的标记,用于识别材料的相关相,如激子绝缘体或超金属的倾向。我们的研究开辟了一个新的材料游乐场,探索高阶VHS之间的相互作用,超导转变温度和电子相关效应的铜酸盐和相关的高Tc超导体。

英文摘要:

Two-dimensional (2D) Van Hove singularities (VHSs) associated with the saddle points or extrema of the energy dispersion usually show logarithmic divergences in the density of states (DOS). However, recent studies find that the VHSs originating from higher-order saddle-points have faster-than-logarithmic divergences, which can amplify electron correlation effects and create exotic states such as supermetals in 2D materials. Here we report the existence of 'high-order' VHSs in the cuprates and related high-Tc superconductors and show that the anomalous divergences in their spectra are driven by the electronic dimensionality of the system being lower than the dimensionality of the lattice. The order of VHS is found to correlate with the superconducting Tc such that materials with higher order VHSs display higher Tc's. We further show that the presence of the normal and higher-order VHSs in the electronic spectrum can provide a straightforward marker for identifying the propensity of a material toward correlated phases such as excitonic insulators or supermetals. Our study opens up a new materials playground for exploring the interplay between high-order VHSs, superconducting transition temperatures and electron correlation effects in the cuprates and related high-Tc superconductors.

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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