Temperature dependence of the superconducting energy gaps in Ca9.35La0.65(Pt3As8)(Fe2As2)5 single crystal

Autor: D. Ahmad, W. J. Choi, Y. I. Seo, Shin-ichi Kimura, Yong Seung Kwon
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Scientific Reports, Vol 8, Iss 1, Pp 1-9 (2018)
ISSN: 2045-2322
DOI: 10.1038/s41598-018-24940-9
Popis: We measured the optical reflectivity R(ω) for an underdoped (Ca0.935La0.065)10(Pt3As8)(Fe2As2)5 single crystal and obtained the optical conductivity $${\sigma }_{1}(\omega )$$ σ 1 ( ω ) using the K-K transformation. The normal state $${\sigma }_{1}(\omega )$$ σ 1 ( ω ) at 30 K is well fitted by a Drude-Lorentz model with two Drude components (ωp1 = 1446 cm−1 and ωp2 = 6322 cm−1) and seven Lorentz components. Relative reflectometry was used to accurately determine the temperature dependence of the superconducting gap at various temperatures below Tc. The results clearly show the opening of a superconducting gap with a weaker second gap structure; the magnitudes for the gaps are estimated from the generalized Mattis-Bardeen model to be Δ1 = 30 and Δ2 = 50 cm−1, respectively, at T = 8 K, which both decrease with increasing temperature. The temperature dependence of the gaps was not consistent with one-band BCS theory but was well described by a two-band (hence, two gap) BCS model with interband interactions. The temperature dependence of the superfluid density is flat at low temperatures, indicating an s-wave full-gap superconducting state.
Databáze: OpenAIRE
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