Probing proximity-induced superconductivity in superconductor-topological Insulator devices via Josephson Interferometry

We are exploring the nature of the proximity-induced order in 3D topological insulators in contact with an s-wave superconductor by phase-sensitive Josephson interferometry. It is predicted that the proximity region should have p-wave pairing symmetry with spin-dependent chiral components. To test this, we compare the behavior of edge and corner junctions on a patterned bilayer of Nb and Bi$_2$Se$_3$ to determine the phase anisotropy that should reflect a mixture of the s and p components. The alternate approach discussed will be measurement of the supercurrent properties in arrays of superconducting islands patterned on top of the topological insulator, which is sensitive to both the current-phase relation of the junctions and the array geometry.