Rashba splitting of Cooper pairs

R. I. Shekhter, O. Entin-Wohlman, M. Jonson, A. Aharony

Published 2016-02-12Version 1

We investigate theoretically the properties of a weak link between two superconducting leads, which has the form of a mechanically-bent non-superconducting nano wire with a strong spin-orbit coupling caused by an electric field. In the Coulomb blockade regime of single-electron tunneling, we find that such a weak link splits the spin states of Cooper pairs tunneling though the link, to an extent that depends on the direction of the electric field. We show that the Josephson current through the link is sensitive to interference between the resulting two transmission channels, one where the spins of both members of a Cooper pair are preserved and one where they are both flipped. As a result, the current is a periodic function both of the bending angle of the nano wire and of the strength of the spin-orbit interaction. In contrast, no spin-orbit induced interference effect can influence the current through a single weak link connecting two normal metals.