Fate of disorder-induced inhomogeneities in strongly correlated d-wave superconductors
Fate of disorder-induced inhomogeneities in strongly correlated d-wave superconductors
复制标题
强相关 d 波超导体中无序引起的不均匀性的命运
DOI：
10.1088/1367-2630/16/10/103018
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发表时间：
2013
影响因子：
3.3
通讯作者：
A. Ghosal
中科院分区：
文献类型：
--
作者：
D. Chakraborty;A. Ghosal
分析了高温超导体中强关联和杂质的复杂相互作用，表明零温下局域有序参数的不均匀性的性质和程度都与简单的Hartree-Fock-Bogoliubov理论的结果有很大的不同。虽然强烈的电子排斥和无序都导致了载流子数量的纳米级不均匀，但我们发现它们相互竞争，导致局域密度的相对平稳变化。我们的自洽计算通过抑制古兹威尔理论中的所有双重占据来修正配对振幅的空间涨落，并阻止形成不同的超导‘岛’。相反，如果忽略了强烈的相关性，这种“岛屿”的存在就会控制着结果。古兹威尔方法中空间结构的重组使这些超导体对杂质不敏感，令人惊讶。这表现为超流体硬度的非常弱的衰变、非对角线的长程有序和高达大无序强度的局域态密度。探索这种稳健性的起源，我们得出结论，潜在的单粒子正常态以一种丰富的方式重塑，使得由这些态配对形成的超导体经历了较弱的但空间相关的有效无序。这种超导性的途径使人想起安德森-ʼ-S定理。我们的结果捕捉到了铜酸盐中的关键实验趋势。
We analyze the complex interplay of the strong correlations and impurities in a high temperature superconductor and show that both the nature and degree of the inhomogeneities at zero temperature in the local-order parameters change drastically from those obtained in a simple Hartree–Fock–Bogoliubov theory. Although both the strong electronic repulsions and disorder contribute to the nanoscale inhomogeneity in the population of charge-carriers, we find they compete with each other, leading to a relatively smooth variation of the local density. Our self-consistent calculations modify the spatial fluctuations in the pairing amplitude by suppressing all the double occupancy within a Gutzwiller formalism and prohibit the formation of distinct superconducting ‘islands’. In contrast, presence of such ‘islands’ controls the outcome if strong correlations are neglected. The reorganization of the spatial structures in the Gutzwiller method makes these superconductors surprisingly insensitive to the impurities. This is illustrated by a very weak decay of superfluid stiffness, off-diagonal long-range order and local density of states up to a large disorder strength. Exploring the origin of such a robustness, we conclude that the underlying one-particle normal states reshape in a rich manner, such that the superconductor formed by pairing these states experiences a weaker but spatially correlated effective disorder. Such a route to superconductivity is evocative of Andersonʼs theorem. Our results capture the key experimental trends in the cuprates.