From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba, K)Fe2As2
From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba, K)Fe2As2
复制标题
DOI：
10.1088/0953-2048/25/8/084013
复制
发表时间：
2012-08-01
影响因子：
3.6
通讯作者：
Taillefer, Louis
中科院分区：
文献类型：
--
作者：
Reid, J-Ph;Juneau-Fecteau, A.;Taillefer, Louis
铁基超导体中的配对状态的本质是一个备受争议的话题。在这里，我们认为，在一种材料，化学计量的铁pnictide KFe 2As 2，有压倒性的证据的d-波配对状态，其特征在于超导间隙中的超导强加的垂直线节点。这一证据进行审查，重点是热导率和杂质散射的临界温度Tc的强烈影响。然后，我们比较KFe 2As 2与Ba 0.6K0.4Fe2As2，通过Ba取代获得，其中配对对称性是s波，T-c高10倍。在同一晶体结构中从d波到s波的跃迁为研究能带结构和配对机制之间的联系提供了难得的机会。我们还比较了KFe 2As 2与结铁基超导体LaFePO的配对对称性可能不是d波，但更可能是s波与偶然的线节点。
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.