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arXiv · 1404.2154

Spin-singlet superconductivity with a full gap in locally non-centrosymmetric SrPtAs

K. Matano·K. Arima·S. Maeda·Y. Nishikubo·K. Kudo·M. Nohara·Guo-qing Zheng
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Abstract

We report $^{195}$Pt-NMR and $^{75}$As-NQR measurements for the locally non-centrosymmetric superconductor SrPtAs where the As-Pt layer breaks inversion symmetry while globally the compound is centrosymmetric. The nuclear spin lattice relaxation rate $1/T_1$ shows a well-defined coherence peak below $T_c$ and decreases exponentially at low temperatures. The spin susceptibility measured by the Knight shift also decreases below $T_c$ down to $T<T_c/6$. These data together with the penetration depth obtained from the NMR spectra can be consistently explained by assuming a spin-singlet superconducting state with a full gap. Our results suggest that the spin-orbit coupling due to the local inversion-breaking is not large enough to bring about an exotic superconducting state, or the inter-layer hopping interaction is larger than the spin-orbit coupling.

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K. Matano, K. Arima, S. Maeda, Y. Nishikubo, K. Kudo, M. Nohara, Guo-qing Zheng. 2014-04-08. Spin-singlet superconductivity with a full gap in locally non-centrosymmetric SrPtAs. https://doi.org/10.1103/physrevb.89.140504

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