论文标题
冷冻自旋比和检测Hund相关性
Frozen spin ratio and the detection of Hund correlations
论文作者
论文摘要
我们提出了一种通过在两个粒子水平上揭示hund相关性的关键标志来识别强烈相关材料的方法。定义特征是在电子密度变化下{\ it冷冻自旋比}响应的{\ it符号}（\ it冷冻自旋比}（长期局部自旋旋转函数除以瞬时值）。根本的物理原因是，该符号与邻近电荷子空间中主要原子多重组和高旋转型的电荷波动强度密切相关。这些波动的占主导地位促进了金属性。冷冻自旋比的温度依赖性可以进一步揭示非富液液体行为，从而进一步揭示了金属状态。我们通过将掺杂的la $ _2 $ cuo $ _4 $和Lafeaso作为Mott和Hund Metals的代表性材料示例分别分析了退化和非分类多型多型哈伯德模型，并通过将掺杂的LA $ _2 $ CUO $ _4 $和LAFEASO来证实了我们的论点。我们的提案应适用于具有未填充整数电子填充物及其掺杂的情况的系统，只要掺杂将电子密度推向半填充。
We propose a way to identify strongly Hund-correlated materials by unveiling a key signature of Hund correlations at the two-particle level. The defining feature is the {\it sign} of the response of the {\it frozen spin ratio} (the long-time local spin-spin correlation function divided by the instantaneous value) under variation of electron density. The underlying physical reason is that the sign is closely related to the strength of charge fluctuations between the dominant atomic multiplets and higher-spin ones in a neighboring charge subspace. It is the predominance of these fluctuations that promotes Hund metallicity. The temperature dependence of the frozen spin ratio can further reveal a non-Fermi-liquid behavior and thus the Hund metal states. We analyze both degenerate and non-degenerate multiorbital Hubbard models and corroborate our argument by taking doped La$_2$CuO$_4$ and LaFeAsO as representative material examples, respectively, of Mott and Hund metals. Our proposal should be applicable to systems with non-half-filled integer electron fillings and their doped cases provided the doping drove the electron density toward the half filling.
