Spontaneous edge accumulation of spin currents in finite-size two-dimensional diffusive spin–orbit coupled SFS heterostructures

Abstract

We theoretically study spin and charge currents through finite-size two-dimensional s -wave superconductor/uniform ferromagnet/ s -wave superconductor ( S / F / S ) junctions with intrinsic spin–orbit interactions (ISOIs) using a quasiclassical approach. Considering experimentally realistic parameters, we demonstrate that the combination of spontaneously broken time-reversal symmetry and lack of inversion symmetry can result in spontaneously accumulated spin currents at the edges of finite-size two-dimensional magnetic S / F / S hybrids. Due to the spontaneous edge spin accumulation, the corners of the F wire host the maximum spin current density. We further reveal that this type edge phenomena is robust and independent of either the actual type of ISOIs or exchange field orientation. Moreover, we study the spin current-phase relations in these diffusive spin–orbit coupled S / F / S junctions. Our results unveil net spin currents, not accompanied by charge supercurrents, that spontaneously accumulate at the sample edges through a modulating superconducting phase difference. Finally, we discuss possible experimental implementations to observe these edge phenomena.

Keywords

• Josephson junctions
• spin transport
• proximity effects
• spin–orbit coupling
• spin triplet pairings
• 74.50.+r