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arXiv 0704.0633cond-mat.supr-concond-mat.str-el
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电子-声子相互作用的d波超导性

d-wave superconductivity from electron-phonon interactions

J. P. Hague

摘要:

我研究电子-声子介导的超导电性在中间耦合和声子频率制度的准二维Holstein模型。我使用一个扩展的Migdal-Eliashberg理论,其中包括顶点校正和空间波动。我发现了一个d波超导态,它是唯一接近半填充的。随着填充量的增加,序参量向s波超导转变。我解释了如何列入顶点校正和空间波动是必不可少的d-波序参量的预测。然后,我讨论了大库仑赝势对超导性的影响(如在当代超导材料中发现的,如铜酸盐),这导致了s波态的破坏,而使d波态不变。

英文摘要:

I examine electron-phonon mediated superconductivity in the intermediate coupling and phonon frequency regime of the quasi-2D Holstein model. I use an extended Migdal-Eliashberg theory which includes vertex corrections and spatial fluctuations. I find a d-wave superconducting state that is unique close to half-filling. The order parameter undergoes a transition to s-wave superconductivity on increasing filling. I explain how the inclusion of both vertex corrections and spatial fluctuations is essential for the prediction of a d-wave order parameter. I then discuss the effects of a large Coulomb pseudopotential on the superconductivity (such as is found in contemporary superconducting materials like the cuprates), which results in the destruction of the s-wave states, while leaving the d-wave states unmodified.

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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