From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba, K)Fe2As2

TitleFrom d-wave to s-wave pairing in the iron-pnictide superconductor (Ba, K)Fe2As2
Publication TypeJournal Article
Year of Publication2012
AuthorsReid JP, Juneau-Fecteau A, Gordon RT, de Cotret SR, Doiron-Leyraud N, Luo XG, Shakeripour H, Chang J, Tanatar MA, Kim H, Prozorov R, Saito T, Fukazawa H, Kohori Y, Kihou K, Lee CH, Iyo A, Eisaki H, Shen B, Wen HH, Taillefer L
Journal TitleSuperconductor Science & Technology
Volume25
Pages084013
Date Published08
Type of ArticleArticle
ISBN Number0953-2048
Accession NumberWOS:000306505100014
Keywordsquasi-particle transport, thermal-conductivity, vortex state, yba2cu3o6.9
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 T-c. We then compare KFe2As2 to Ba0.6K0.4Fe2As2, obtained by Ba substitution, where the pairing symmetry is s-wave and the T-c 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 the pairing mechanism. We also compare KFe2As2 with 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.

URL<Go to ISI>://WOS:000306505100014
DOI10.1088/0953-2048/25/8/084013
Alternate JournalSupercond. Sci. Technol.