Spin–orbit coupling and anomalous Josephson effect in nanowires

A superconductor-semiconducting nanowire-superconductor heterostructure in the presence of spin–orbit coupling and magnetic field can support a supercurrent even in the absence of phase difference between the superconducting electrodes. We investigate this phenomenon—the anomalous Josephson effect—employing a model capable of describing many bands in the normal region. We discuss the geometrical and symmetry conditions required to have a finite anomalous supercurrent, and in particular we show that this phenomenon is enhanced when the Fermi level is located close to a band opening in the normal region.