Device for extraction of Majorana current by means of Fraunhofer diffraction in proximitized superconducting arrays

We propose a geometry in which the supercurrent carried by Majorana zero modes dominates the ordinary supercurrent. The devices is tunable through the Fraunhofer diffraction. The contribution of the Majorana current is further amplified by organizing an array of conducting channels. This system can act as a tunable source of Majorana current.
We performed transport experiment on superconductor-topological insulator-superconductor Josephson junctions array consisting of square niobium islands on a Bi₂Se₃ film.
According to a Fraunhofer diffraction model, when perpendicular magnetic field is applied such that there is exactly one flux quantum in each junction we should achieve the desired regime where Majorana current is the only supercurrent in the sample. Our results indicate that the conductance peak corresponding to ordinary supercurrent indeed disappears at such magnetic flux bias. Yet, even at this flux bias (frustration f=2) the sample resistance approaches zero rapidly with cooling. This divergence of the conductance at the flux when the ordinary superconductivity is suppressed is taken as evidence for Majorana mode supercurrent.
Geometrical inhomogeneity has been modelled and, apparently, cannot account the observed zeroing of the resistance.