Eur. Phys. J. B (2013) 86: 190
https://doi.org/10.1140/epjb/e2013-30981-x

Regular Article

Spin Josephson current in a ferromagnet/noncentrosymmetric superconductor junction

Department of Physics, Southeast University, Nanjing 210096, P.R. China

^a e-mail: renchongdan@hotmail.com

Received: 26 October 2012
Received in final form: 3 November 2012
Published online: 24 April 2013

Abstract

We investigate the equilibrium spin transport in a ferromagnet/noncentrosymmetric superconductor (FM/NCS) junction where the NCS has a dominant triplet order parameter and helical edge state. Based on the symmetry analysis and numerical calculation, we demonstrate that there is a nonzero spin supercurrent flowing in the junction, which stems from the exchange coupling between the FM magnetization and triplet Cooper-pair spin. It is also found that a transverse spin current other than the helical edge spin current is flowing along the interface of the junction, and its polarization is related to the longitudinal spin supercurrent. Besides, an equilibrium Hall current is also shown to flow along the junction’s interface due to the broken time-reversal symmetry from the FM.