Temperature and Spatial Dependence of the Superconducting and Pseudogap of NdFeAsO0.86F0.14 - Condensed Matter > SuperconductivityReportar como inadecuado




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Abstract: The discovery of superconductivity with a critical temperature exceeding 55 Kin the iron-oxypnictides and related compounds has quite suddenly given thecommunity a new set of materials - breaking the tyranny of copper. This newclass of materials raises fundamental questions related to the origin of theelectron pairing in the superconducting state and to the similarity tosuperconductivity in the cuprates. Here, we report spatially resolvedmeasurements using scanning tunneling microscopy-spectroscopy STM-STS of thenewly discovered iron-based layered superconductor NdFeAsO0.86F0.14 Tc = 48 Kas a function of temperature. The tunneling spectra at 17 K show a suppressionof spectral intensity within +- 10 meV, indicative of the opening of thesuperconducting gap SG. Below Tc, the sample exhibits two characteristic gaps- a large one 18 meV and a small one 9 meV - existing in different spatiallocations. Both gaps are closed above Tc at the bulk Tc, but only the small gapcan be fitted with a superconducting gap function. This gap displays a BCS -like order parameter. Above Tc, at the same location where the small gap wasobserved, a pseudogap PG opens abruptly at a temperature just above Tc andcloses at 120 K. In contrast to the cuprates, the SG and PG have competingorder parameters.



Autor: M. H. Pan, X. B. He, G. R. Li, J. F. Wendelken, R. Jin, A. S. Sefat, M. A. McGuire, B. C. Sales, D. Mandrus, E. W. Plummer

Fuente: https://arxiv.org/







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