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arXiv · 1106.4430

Optical conductivity of Ba0.6 K0.4 Fe2 As2 : The effect of in-plane and out-of-plane doping in the superconducting gap

Y. M. Dai·B. Xu·B. Shen·H. H. Wen·X. G. Qiu·R. P. S. M. Lobo
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Abstract

We measured the in-plane optical conductivity of a nearly optimally doped (Ba,K)Fe2As2 single crystal with Tc = 39.1 K. Upon entering the superconducting state the optical conductivity below ~20 meV vanishes, strongly suggesting a fully gapped system. A BCS-like fit requires two different isotropic gaps to describe the optical response of this material. The temperature dependence of the gaps and the penetration depth suggest a strong interband coupling, but no impurity scattering induced pair breaking is present. This contrasts to the large residual conductivity observed in optimally doped Ba(Fe,Co)2As2 and strongly supports an s(+/-) gap symmetry for these compounds.

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Y. M. Dai, B. Xu, B. Shen, H. H. Wen, X. G. Qiu, R. P. S. M. Lobo. 2015-01-08. Optical conductivity of Ba0.6 K0.4 Fe2 As2 : The effect of in-plane and out-of-plane doping in the superconducting gap. https://doi.org/10.1209/0295-5075%2F104%2F47006

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