Josephson Hall current in a noncentrosymmetric superconductor/ferromagnet/superconductor junction

Abstract

We theoretically study the transverse spin and charge transport in a 2D noncentrosymmetric superconductor (NCS)/ferromagnet (FM)/superconductor Josephson junction, in which the NCS has a dominant triplet order parameter and helical edge states. It is predicted that both equilibrium spin and charge Hall currents can flow transversely in the junction and are driven by the superconducting phase gradient. The physical origin of the Josephson Hall current is the broken time-reversal symmetry due to the FM and the mixing of the helical edge states. The Hall currents are sensitive to the FM magnetization direction, and the planar magnetization component is vitally important because it can lead to a spin flip effect that makes the Cooper pairs tunnel between unequal chiral edge states of the two NCSs.