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arXiv · 1509.05021

Coexistence of Clean- and Dirty-limit Superconductivity in LiFeAs

Y. M. Dai·H. Miao·L. Y. Xing·X. C. Wang·C. Q. Jin·H. Ding·C. C. Homes
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Abstract

The optical properties of LiFeAs with $T_c \simeq$ 18 K have been determined in the normal and superconducting states. The superposition of two Drude components yields a good description of the low-frequency optical response in the normal state. Below $T_c$, the optical conductivity reveals two isotropic superconducting gaps with $\Delta_{1} \simeq 2.9$ $\pm$ 0.2 meV and $\Delta_{2} \simeq 5.5$ $\pm$ 0.4 meV. A comparison between the superconducting-state Mattis-Bardeen and the normal-state Drude components, in combination with a spectral weight analysis, indicates that the spectral weight associated with a band which has a very small scattering rate is fully transferred to the superfluid weight upon the superconducting condensate. These observations provide clear evidence for the coexistence of clean- and dirty-limit superconductivity in LiFeAs.

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Y. M. Dai, H. Miao, L. Y. Xing, X. C. Wang, C. Q. Jin, H. Ding, C. C. Homes. 2015-09-16. Coexistence of Clean- and Dirty-limit Superconductivity in LiFeAs. https://doi.org/10.1103/physrevb.93.054508

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