Two-gap time reversal symmetry breaking superconductivity in noncentrosymmetric LaNiC2

arXiv: Superconductivity Pub Date : 2020-11-04 DOI:10.1103/PHYSREVB.103.014511

S. Sundar, S. Dunsiger, S. Gheidi, K. Akella, A. M. Cot'e, H. U. Özdemir, N. R. Lee-Hone, D. Broun, E. Mun, F. Honda, Y. Sato, T. Koizumi, R. Settai, Y. Hirose, I. Bonalde, J. Sonier

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引用次数: 4

Abstract

We report a $\mu$SR investigation of a non-centrosymmetric superconductor (LaNiC$_2$) in single crystal form. Compared to previous $\mu$SR studies of non-centrosymmetric superconducting polycrystalline and powder samples, the unambiguous orientation of single crystals enables a simultaneous determination of the absolute value of the magnetic penetration depth and the vortex core size from measurements that probe the magnetic field distribution in the vortex state. The magnetic field dependence of these quantities unambiguously demonstrates the presence of two nodeless superconducting energy gaps. In addition, we detect weak internal magnetic fields in the superconducting phase, confirming earlier $\mu$SR evidence for a time-reversal symmetry breaking superconducting state. Our results suggest that Cooper pairing in LaNiC$_2$ is characterized by the same interorbital equal-spin pairing model introduced to describe the pairing state in the centrosymmetric superconductor LaNiGa$_2$.

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非中心对称LaNiC2的双间隙时间反转对称性破缺超导性

我们报道了单晶形式的非中心对称超导体(LaNiC$_2$)的SR研究。与之前对非中心对称超导多晶和粉末样品的研究相比，单晶的明确取向使得通过测量漩涡状态下的磁场分布可以同时确定磁穿透深度的绝对值和漩涡核的大小。这些量的磁场依赖性明确地证明了两个无节点超导能隙的存在。此外，我们在超导相中检测到微弱的内部磁场，证实了时间反转对称性破缺超导态的早期$\mu$SR证据。我们的研究结果表明，LaNiC$_2$中的Cooper配对与描述中心对称超导体LaNiC$_2$中的配对状态的轨道间等自旋配对模型相同。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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arXiv: Superconductivity

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