A Josephson junction (JJ) couples the supercurrent flowing between two weakly linked superconductors to the phase difference between them via a current-phase relation (CPR). While a sinusoidal CPR is expected for conventional junctions with insulating weak links, devices made from some exotic materials may give rise to unconventional CPRs and unusual Josephson effects. In this work, we present such a case: we investigate the proximity-induced superconductivity in SnTe nanowires by incorporating them as weak links in JJs and observe a deviation from the standard CPR. We report on indications of an unexpected breaking of time-reversal symmetry in these devices, detailing the unconventional characteristics that reveal this behavior. These include an asymmetric critical current in the DC Josephson effect, a prominent second harmonic in the AC Josephson effect, and a magnetic diffraction pattern with a minimum in critical current at zero magnetic field. The analysis examines how multiband effects and the experimentally visualized ferroelectric domain walls give rise to this behavior, giving insight into the Josephson effect in materials that possess ferroelectricity and/or multiband superconductivity.

约瑟夫森结 (JJ) 通过电流-相位关系 (CPR) 将两个弱连接超导体之间流动的超电流耦合到它们之间的相位差。虽然对于具有绝缘薄弱环节的传统结点预计会出现正弦 CPR，但由一些特殊材料制成的设备可能会引起非常规 CPR 和不寻常的约瑟夫森效应。在这项工作中，我们提出了这样一个案例：我们通过将 SnTe 纳米线作为 JJ 中的薄弱环节来研究邻近感应超导性，并观察与标准 CPR 的偏差。我们报告了这些设备中时间反转对称性意外破坏的迹象，详细说明了揭示这种行为的非常规特征。这些包括直流约瑟夫森效应中的不对称临界电流，AC Josephson 效应中突出的二次谐波，以及零磁场下临界电流最小的磁衍射图案。该分析检查了多波段效应和实验可视化的铁电畴壁如何引起这种行为，从而深入了解具有铁电性和/或多波段超导性的材料中的约瑟夫森效应。