From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba,K)Fe2As2
Abstract
The nature of the pairing state in iron-based superconductors is the subject of much debate. Here we argue that in one material, the stoichiometric iron pnictide KFe2As2, there is overwhelming evidence for a d-wave pairing state, characterized by symmetry-imposed vertical line nodes in the superconducting gap. This evidence is reviewed, with a focus on thermal conductivity and the strong impact of impurity scattering on the critical temperature Tc. We then compare KFe2As2 to Ba0.6K0.4Fe2As2, obtained by Ba substitution, where the pairing symmetry is s-wave and the Tc is ten times higher. The transition from d-wave to s-wave within the same crystal structure provides a rare opportunity to investigate the connection between band structure and pairing mechanism. We also compare KFe2As2 to the nodal iron-based superconductor LaFePO, for which the pairing symmetry is probably not d-wave, but more likely s-wave with accidental line nodes.
Keywords
Cite
@article{arxiv.1207.5719,
title = {From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba,K)Fe2As2},
author = {J. -Ph. Reid and A. Juneau-Fecteau and R. T. Gordon and S. Rene de Cotret and N. Doiron-Leyraud and X. G. Luo and H. Shakeripour and J. Chang and M. A. Tanatar and H. Kim and R. Prozorov and T. Saito and H. Fukazawa and Y. Kohori and K. Kihou and C. H. Lee and A. Iyo and H. Eisaki and B. Shen and H. -H. Wen and Louis Taillefer},
journal= {arXiv preprint arXiv:1207.5719},
year = {2015}
}