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arXiv · 1102.3655

Symmetry analysis of possible superconducting states in KxFe2Se2 superconductors

I. I. Mazin
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Abstract

A newly discovered family of the Fe-based superconductors is isostructural with the so-called 122 family of Fe pnictides, but has a qualitatively different doping state. Early experiments indicate that superconductivity is nodeless, yet prerequisites for the $s_\pm$ nodeless state (generally believed to be realized in Fe superconductors) are missing. It is tempting to assign a $d-$ wave symmetry to the new materials, and it does seem at first glance that such a state may be nodeless. Yet a more careful analysis shows that it is not possible, given the particular 122 crystallography, and that the possible choice of admissible symmetries is severly limited: it is either a conventional single-sign $s_{+}$ state, or another $s_\pm$ state, different from the one believed to be present in other Fe-based superconductors.

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I. I. Mazin. 2011-02-17. Symmetry analysis of possible superconducting states in KxFe2Se2 superconductors. https://doi.org/10.1103/physrevb.84.024529

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