Josephson Interferometry of Zig-Zag Junctions Demonstrating Enhanced Localization*

Josephson junctions on mercury telluride quantum wells combine strong spin-orbit effects, s-wave superconductivity, and arbitrary lithographic design. This platform facilitates both the study of induced superconductivity in the quantum well and topological states in quasi-1D systems. While zero bias peaks have been observed in these quasi-1D systems, small topological gaps and poor confinement of the 0-D topological states makes their assignment as Majorana fermions challenging. Recent theoretical work suggests an order of magnitude enhancement in the topological gap and localization when the Josephson junction is fabricated in a zig-zag geometry [1]. In this work, we provide the first characterization of zig-zag geometry junctions and demonstrate enhanced localization of electrons within the junction.

[1] T. Laeven, B. Nijholt, M. Wimmer, A. Akhmerov. arxiv:1903.06168.