论文标题
非中心超级导体LA $ _ {7} $ ni $ _ {3} $中的时间反向对称性断裂和多映射超导率
Time-reversal symmetry breaking and multigap superconductivity in the noncentrosymmetric superconductor La$_{7}$Ni$_{3}$
论文作者
论文摘要
$ _ {7} $ fe $ _ {3} $超导体家族为非常规超导性提供了丰富的操场。 la $ _7 $ ni $ _3 $是该家族的最新成员，我们在这里通过热力学和MUON旋转旋转和放松测量进行调查。我们的特定热数据提供了两个不同和近似各向同性的超导间隙的证据。较大的差距的值略高于弱耦合BCS理论，表明存在显着相关性。这些观察结果通过横向场摩恩旋转测量结果证实。此外，零场的测量结果揭示了超导状态下的较小的内部场，该磁场发生在超导性的发作附近，并表明超导顺序参数违反了时间反向对称性。我们讨论了两个可能的微观场景 - 一个非常规的$ e_ {2}（1，i）$ state和$ s+i \，s $超导体，这是通过两个连续的过渡达到的 - 并说明哪些相互作用将有利于这些阶段。我们的结果确定了la $ _ {7} $ ni $ _ {3} $作为TH $ _ {7} $ fe $ _ {3} $ family的第一个成员，显示时间反向对称性 - 对称性 - 破坏和多式超导性。
The Th$_{7}$Fe$_{3}$ family of superconductors provides a rich playground for unconventional superconductivity. La$_7$Ni$_3$ is the latest member of this family, which we here investigate by means of thermodynamic and muon spin rotation and relaxation measurements. Our specific heat data provides evidence for two distinct and approximately isotropic superconducting gaps. The larger gap has a value slightly higher than that of weak-coupling BCS theory, indicating the presence of significant correlations. These observations are confirmed by transverse-field muon-rotation measurements. Furthermore, zero-field measurements reveal small internal fields in the superconducting state, which occur close to the onset of superconductivity and indicate that the superconducting order parameter breaks time-reversal symmetry. We discuss two possible microscopic scenarios -- an unconventional $E_{2}(1,i)$ state and an $s+i\,s$ superconductor, which is reached by two consecutive transitions -- and illustrate which interactions will favor these phases. Our results establish La$_{7}$Ni$_{3}$ as the first member of the Th$_{7}$Fe$_{3}$ family displaying both time-reversal-symmetry-breaking and multigap superconductivity.
