Unusual superconductivity in the topological nodal-line semimetal candidate Sn x NbSe 2-δ
Unusual superconductivity in the topological nodal-line semimetal candidate Sn x NbSe 2-δ
复制标题
拓扑节点线半金属候选 Sn x NbSe 2-δ 中的异常超导性
DOI：
10.1088/1742-6596/2164/1/012008
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Nakajima, Yasuyuki
中科院分区：
文献类型：
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作者：
Munir, Riffat;Hasan Siddiquee, K A;Dissanayake, Charuni;Kumarasinghe, Kapila;Hu, Xinzhe;Takano, Yasumasa;Choi, Eun Sang;Nakajima, Yasuyuki
我们报告了具有非中心对称晶体结构的拓扑节点线半金属候选 Sn x NbSe 2-δ 的超导性。 Sn x NbSe 2-δ 的超导转变温度T c 随Sn浓度x和Se缺乏量δ变化很大，达到12 K，相对高于已知的拓扑超导体。该化合物的上临界场表现出不同寻常的温度依赖性，与传统 II 型超导体的 WHH 理论不一致。在低 T c 样品中，平行于 ab 平面的上临界场的零温度极限超过了根据简单 BCS 弱耦合模型估计的泡利顺磁极限约 2 倍，表明稳定在 Sn x NbSe 2-δ 中的异常超导性。加上强大的抗无序超导性，这些观察结果表明 Sn x NbSe 2-δ 是探索拓扑超导性的有希望的候选者。
We report the superconductivity of the topological nodal-line semimetal candidate Sn x NbSe 2-δ with a noncentrosymmetric crystal structure. The superconducting transition temperature T c of Sn x NbSe 2-δ drastically varies with the Sn concentration x and the Se deficiency δ, and reaches 12 K, relatively higher than those of known topological superconductors. The upper critical field of this compound shows unusual temperature dependence, inconsistent with the WHH theory for conventional type-II superconductors. In a low-T c sample, the zero-temperature limit of the upper critical field parallel to the ab plane exceeds the Pauli paramagnetic limit estimated from the simple BCS weak coupling model by a factor of∼ 2, suggestive of unusual superconductivity stabilized in Sn x NbSe 2-δ. Together with the robust superconductivity against disorder, these observations indicate that Sn x NbSe 2-δ is a promising candidate to explore topological superconductivity.