Josephson Detection of Time Reversal Symmetry Broken Superconductivity in SnTe Nanowires.

Exotic superconductivity, such as high T$_C$, topological, and heavy-fermion superconductors, often rely on phase sensitive measurements to determine the underlying pairing. Here we investigate the proximity-induced superconductivity in nanowires of SnTe, where a $s\pm is^{\prime}$ superconducting state is produced that lacks the time-reversal and valley-exchange symmetry of the parent SnTe. A systematic breakdown of three conventional characteristics of Josephson junctions -- the DC Josephson effect, the AC Josephson effect, and the magnetic diffraction pattern -- fabricated from SnTe nanowire weak links elucidates this novel superconducting state. Further, this time-reversal broken state allows for a new path Majorana bound states in materials with an even number of bands: evidence of a Majorana bound state in SnTe nanowires is achieved in this Letter from measurements of the AC Josephson effect. This work represents the definitive phase-sensitive measurement of novel $s\pm is^{\prime}$ superconductivity, providing a new route to the investigation of fractional vortices [1,2], topological superconductivity, topological phase transitions, and new types of Josephson-based devices in proximity-induced multiband superconductors [3,4].