标题： 非平凡$\mathcal{Z}_2$近似准晶体中的超导性观测 显示英文标题

标题： Observation of superconductivity in a nontrivial $\mathcal{Z}_2$ approximant quasicrystal

摘要： 超导性和非平凡拓扑在量子材料中是高度期望的现象。 虽然许多拓扑晶体材料已被发现具有超导性，但它们在准晶体——具有独特非周期性但有序结构的材料——中的存在仍大多未被探索。 在本工作中，我们报告了在十重准晶体Al$_{13}$Os$_{4}$的单斜近似体中发现的超导性，该材料表现出高的超导转变温度和非平凡的电子结构。 电阻率、磁化率、比热和$\mu$SR 测量证实了临界温度为$\sim5.47$K 的超导性。详细的电子结构和对称性分析揭示了具有$\mathcal{Z}_{2}=1$和自旋极化导电表面态的非平凡态。 重要的是，我们发现了三维鞍点范霍夫奇异性，在费米能级具有显著平坦的能量色散，这可以增强超导性。 我们的结果突显了Al$_{13}$Os$_{4}$中超导性和非平凡电子态之间的丰富相互作用，证明其作为探索准晶体材料中非常规超导态的独特平台。 显示英文摘要

摘要： Superconductivity and nontrivial topology are highly sought-after phenomena in quantum materials. While many topological crystalline materials have been found to exhibit superconductivity, their presence in quasicrystals - materials with a unique aperiodic yet ordered structure - has remained largely unexplored. In this work, we report the discovery of superconductivity in a monoclinic approximant to the decagonal quasicrystal Al$_{13}$Os$_{4}$, that exhibits a high superconducting transition temperature and a nontrivial electronic structure. The resistivity, magnetization, specific heat, and $\mu$SR measurements confirm superconductivity with a critical temperature of $\sim5.47$ K. Detailed electronic structure and symmetry analysis reveal nontrivial state with $\mathcal{Z}_{2}=1$ and spin-polarized conducting surface states. Importantly, we identify three-dimensional saddle point van Hove singularities with substantial flat energy dispersion at the Fermi level, which can enhance superconductivity. Our results highlight a rich interplay between superconductivity and nontrivial electronic states in Al$_{13}$Os$_{4}$, demonstrating it as a unique platform for exploring unconventional superconducting states in quasicrystalline materials.