Tunneling spin Hall effect induced by unconventional $p$-wave magnetism

Abstract

We propose a tunneling spin Hall effect in a normal metal/$p$-wave magnet/superconductor junction. It is found that the Andreev reflection in the normal lead is spin-dependent and exhibits strong asymmetry with respect to the transverse momentum, giving rise to a pure transverse spin Hall current with zero net charge. The transverse spin conductance is analytically derived using the nonequilibrium Green's function approach, revealing that the predicted spin Hall effect is governed by the direction of the Fermi surface splitting in the $p$-wave magnet. A finite transverse spin current with a large spin Hall angle arises when the line connecting the centers of the spin-split Fermi surfaces is perpendicular to the normal direction of the junction, which indicates a highly efficient charge-to-spin conversion, suggesting potential applications in spintronic devices.