Abstract

We analyze the behavior of thermal fluctuations of the superconducting order parameter with extended s-wave and \({{d}_{{{{x}^{2}} - {{y}^{2}}}}}\)-wave symmetry. For this purpose, we develop a method of self-consistent consideration of the order parameter fluctuations and charge carrier scatterers by fluctuations of coupled electron pairs using the theory of functional integration. The study is performed based on the quasi-two-dimensional one-band model with attraction between electrons located at neighboring sites. We obtain the distribution functions of the phase fluctuation probabilities depending on temperature, charge carrier concentrations, and model parameters. It is shown that the phase of the order parameter in the superconducting region is coherent, and the density of states has a dip at the Fermi level. In approaching the incoherent region of the phase diagram, the dip in the density of states disappears simultaneously with the loss of phase coherence. At the same time, the order parameter amplitude averaged over fluctuations remains finite at any temperature and concentration of charge carriers. Our results show that the pseudogap state cannot be explained in the frames of this scenario.

中文翻译：

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具有s和d对称性的单重态超导相中的涨落的自洽考虑

摘要

我们分析了具有扩展s波和\（{{d} _ {{{{x} ^ {2}}-{{y} ^ {2}}}}} \\的超导阶跃参数的热涨落行为。）波对称性。为此，我们使用功能积分理论开发了一种通过耦合电子对的波动来自洽考虑阶跃参数波动和电荷载流子散射的方法。该研究是基于准二维一带模型进行的，其中相邻位置的电子之间具有吸引力。我们根据温度，电荷载流子浓度和模型参数获得相位波动概率的分布函数。结果表明，超导区域中有序参数的相位是相干的，并且态密度在费米能级上有一个下降。在接近相图的非相干区域时，状态密度的下降与相干的损失同时消失。同时，在任何温度和电荷载流子浓度下，在波动中平均的阶次参数幅度都保持有限。我们的结果表明，在这种情况下无法解释伪间隙状态。