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arXiv 1003.2389cond-mat.supr-con
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多带金属中的超导性和自旋密度波

Superconductivity and spin-density-waves in multi-band metals

A. B. Vorontsov, M. G. Vavilov, A. V. Chubukov

摘要:

本文详细描述了具有s波超导和反铁磁自旋密度波关联的双带准二维金属。我们提出了一个通用的方法,并使用它来研究的影响之间的差异的形状和面积的两个费米面的相图。特别是,我们确定了在不同的温度和掺杂的SC和SDW订单共存的条件。我们认为,一个传统的s波SC秩序共存SDW秩序只有在非常低的$T$和在一个非常小的参数范围。一个扩展的s波超导,SC间隙改变两个带之间的符号,共存于反铁磁SDW在更广泛的参数和温度范围内,但即使对于这个SC顺序的SDW和SC的区域仍然可以分开的第一阶过渡。我们发现,共存范围变得更大,如果SDW阶是不相称的。我们将我们的研究结果应用于铁基磷属元素化物材料,在其中一些SDW和SC订单的共存已被检测到。

英文摘要:

We present a detailed description of two-band quasi-2D metals with s-wave superconducting (SC) and antiferromagnetic spin-density wave (SDW) correlations. We present a general approach and use it to investigate the influence of the difference between the shapes and the areas of the two Fermi surfaces on the phase diagram. In particular, we determine the conditions for the co-existence of SC and SDW orders at different temperatures and dopings. We argue that a conventional s-wave SC order co-exists with SDW order only at very low $T$ and in a very tiny range of parameters. An extended s-wave superconductivity, for which SC gap changes sign between the two bands, co-exists with antiferromagnetic SDW over a much wider range of parameters and temperatures, but even for this SC order the regions of SDW and SC can still be separated by a first order transition. We show that the co-existence range becomes larger if SDW order is incommensurate. We apply our results to iron-based pnictide materials, in some of which co-existence of SDW and SC orders has been detected.

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