Magneto-Josephson effects in junctions with Majorana bound states

Liang Jiang, David Pekker, Jason Alicea, Gil Refael, Yuval Oreg, Arne Brataas, Felix von Oppen

Published 2012-06-07Version 1

We investigate 1D quantum systems that support Majorana bound states at interfaces between topologically distinct regions. In particular, we show that there exists a duality between particle-hole and spin degrees of freedom in certain spin-orbit-coupled 1D platforms such as topological insulator edges. This duality results in a spin analogue of previously explored `fractional Josephson effects'---that is, the spin current flowing across a magnetic junction exhibits 4\pi-periodicity in the relative magnetic field angle across the junction. Furthermore, the interplay between the particle-hole and spin degrees of freedom results in unconventional magneto-Josephson effects, such that the Josephson current is a function of the magnetic field orientation with periodicity 4\pi.