Josephson current via an isolated Majorana zero mode

We study the equilibrium dc Josephson current in a junction between an s-wave and a topological superconductor. Cooper pairs from the s-wave superconducting lead can transfer to the topological side either via an unpaired Majorana zero mode localized near the junction or via the above-gap continuum states. We find that theMajorana contribution to the supercurrent can be switched on when time-reversal symmetry in the conventional lead is broken, e.g., by an externally applied magnetic field inducing a Zeeman splitting. Moreover, if the magnetic field has a component in the direction of the effective spin-orbit field, there will be a Majorana-induced anomalous supercurrent at zero phase difference. These behaviors may serve as a signature characteristic of Majorana zero modes and are accessible to devices with only superconducting contacts.

Automated summary

The study reveals that the contribution of Majorana to the supercurrent can be activated when time-reversal symmetry in the conventional lead is broken. Moreover, there will be a Majorana-induced anomalous supercurrent when the magnetic field has a component in the direction of the effective spin-orbit field. These findings highlight the characteristic behaviors of Majorana zero modes that can be accessed with devices having only superconducting contacts.