Combining topology and superconductivity providesa powerful tool for investigating fundamental physics as well as aroute to fault-tolerant quantum computing. There is mountingevidence that the Fe-based superconductor FeTe0.55Se0.45 (FTS)may also be topologically nontrivial. Should the superconductingorder be s±, then FTS could be a higher order topologicalsuperconductor with helical hinge zero modes (HHZMs). To testthe presence of these modes, we have fabricated normal-metal/superconductor junctions on different surfaces via 2D atomic crystalheterostructures. As expected, junctions in contact with the hingereveal a sharp zero bias anomaly that is absent when tunnelingpurely into the c-axis. Additionally, the shape and suppression withtemperature are consistent with highly coherent modes  [ Read More ]