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arXiv · 0902.2667

Point contact Andreev reflection spectroscopy of superconducting energy gaps in 122-type family of iron pnictides

P. Samuely·Z. Pribulova·P. Szabo·G. Pristas·S. L. Bud'ko·P. C. Canfield
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Abstract

A brief overview of the superconducting energy gap studies on 122-type family of iron pnictides is given. It seems that the situation in the hole-doped Ba1-xKxFe2As2 is well resolved. Most of the measurements including the presented here point-contact Andreev reflection spectra agree on existence of multiple nodeless gaps in the excitation spectrum of this multiband system. The gaps have basically two sizes - the small one with a strength up to the BCS weak coupling limit and the large one with a very strong coupling with 2Delta/kTc ~ 6 - 8. In the electron doped Ba(Fe1-xCox)2As2 the most of the experiments including our point contact measurements reveal in quite broadened spectra only a single gap with a strong coupling strength. The high precision ARPES measurements on this system identified two gaps but very close to each other, both showing a strong coupling with 2Delta/kTc ~ 5 and 6, respectively.

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P. Samuely, Z. Pribulova, P. Szabo, G. Pristas, S. L. Bud'ko, P. C. Canfield. 2009-02-16. Point contact Andreev reflection spectroscopy of superconducting energy gaps in 122-type family of iron pnictides. https://doi.org/10.1016/j.physc.2009.03.037

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