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arXiv · 1805.03416

Fully gapped spin-singlet superconductivity in noncentrosymmetric PbTaSe$_2$ : $^{207}$Pb-NMR

S. Maeda·K. Matano·Guo-qing Zheng
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Abstract

We report the $^{207}$Pb nuclear magnetic resonance (NMR) measurements on polycrystalline sample of PbTaSe$_2$ with noncentrosymmetric crystal structure and topological electronic band. The nuclear spin-lattice relaxation rate $1/T_1$ shows a suppressed coherence peak below the superconducting transition temperature $T_{\rm c}$ = 4.05 K and decreases as an exponential function of temperature. The penetration depth derived from the NMR spectrum is almost temperature independent below $T$ = 0.7 $T_{\rm c}$. The Knight shift $K$ decreases below $T_{\rm c}$. These results suggest spin-singlet superconductivity with a fully-opened gap $2\Delta = 3.5$ $k_{\rm B}T_{\rm c}$ in PbTaSe$_2$.

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S. Maeda, K. Matano, Guo-qing Zheng. 2018-05-09. Fully gapped spin-singlet superconductivity in noncentrosymmetric PbTaSe$_2$ : $^{207}$Pb-NMR. https://doi.org/10.1103/physrevb.97.184510

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