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arXiv · 1102.0834

Fully gapped superconductivity in Ni-pnictide superconductors BaNi2As2 and SrNi2P2

N. Kurita·F. Ronning·C. F. Miclea·Y. Tokiwa·E. D. Bauer·A. Subedi·D. J. Singh·H. Sakai·J. D. Thompson·R. Movshovich
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Abstract

We have performed low-temperature specific heat $C$ and thermal conductivity $κ$ measurements on the Ni-pnictide superconductors BaNi$_2$As$_2$ ($T_\mathrm{c}$=0.7 K and SrNi$_2$P$_2$ ($T_\mathrm{c}$=1.4 K). The temperature dependences $C(T)$ and $κ(T)$ of the two compounds are similar to the results of a number of s-wave superconductors. Furthermore, the concave field responses of the residual $κ$ for BaNi$_2$As$_2$ rules out the presence of nodes on the Fermi surfaces. We postulate that fully gapped superconductivity could be universal for Ni-pnictide superconductors. Specific heat data on Ba$_{0.6}$La$_{0.4}$Ni$_2$As$_2$ shows a mild suppression of $T_\mathrm{c}$ and $H_\mathrm{c2}$ relative to BaNi$_2$As$_2$.

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N. Kurita, F. Ronning, C. F. Miclea, Y. Tokiwa, E. D. Bauer, A. Subedi, D. J. Singh, H. Sakai, J. D. Thompson, R. Movshovich. 2011-02-04. Fully gapped superconductivity in Ni-pnictide superconductors BaNi2As2 and SrNi2P2. https://doi.org/10.1088/1742-6596%2F273%2F1%2F012097

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