The BCS-like gap in superconductor SmFeAsO_0.85F_0.15

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dc.creatorChen, T. Y.
dc.creatorTesanovic, Z.
dc.creatorLiu, R. H.
dc.creatorChen, X. H.
dc.creatorChien, C. L.
dc.date2008-05-29
dc.date.accessioned2026-07-07T09:50:51Z
dc.date.available2026-07-07T09:50:51Z
dc.descriptionSince the discovery of superconductivity in the cuprates two decades ago, it has been firmly established that the CuO_2 plane is consequential for high T_C superconductivity and a host of other very unusual properties. A new family of superconductors with the general composition of LaFeAsO_(1-x)F_x has recently been discovered but with the conspicuous lacking of the CuO_2 planes, thus raising the tantalizing questions of the different pairing mechanisms in these oxypnictide superconductors. Intimately related to pairing in a superconductor are the superconducting gap, its value, structure, and temperature dependence. Here we report the observation of a single gap in the superconductor SmFeAsO_0.85F_0.15 with T_C = 42 K as measured by Andreev spectroscopy. The gap value of 2Delta = 13.34+/-0.3 meV gives 2Delta/k_BT_C = 3.68, close to the BCS prediction of 3.53. The gap decreases with temperature and vanishes at T_C in a manner consistent with the Bardeen-Cooper-Schrieffer (BCS) prediction but dramatically different from that of the pseudogap behavior in the cuprate superconductors. Our results clearly indicate a nodeless gap order parameter, which is nearly isotropic in size across different sections of the Fermi surface, and are not compatible with models involving antiferromagnetic fluctuations, strong correlations, t-J model, and the like, originally designed for cuprates.
dc.description8 pages, 3 figures
dc.identifierhttps://arxiv.org/abs/0805.4616
dc.identifierhttp://arxiv.org/abs/0805.4616
dc.identifierNature 453, 1224-1227 (26 June 2008)
dc.identifierdoi:10.1038/nature07081
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/165084
dc.subjectSuperconductivity
dc.titleThe BCS-like gap in superconductor SmFeAsO_0.85F_0.15
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