Enhanced spin Hall effect by resonant skew scattering in orbital-selective Kondo effect

TL;DR

This paper investigates how resonant skew scattering enhances the spin Hall effect in Au metal, attributing the large spin Hall angle to the orbital-selective Kondo effect of Fe impurities, with implications for spintronics.

Contribution

It reveals that the orbital-dependent Kondo effect in Fe-doped Au significantly amplifies the spin Hall effect through resonant skew scattering, a novel insight into spin-orbit interactions.

Findings

Gigantic spin Hall angle of ~0.1 explained by orbital-selective Kondo effect.

Resonant skew scattering enhances spin-orbit interaction in $t_{2g}$-orbitals.

Impurities with 5d orbitals also influence the spin Hall effect.

Abstract

The enhanced spin Hall effect in Au metal due to the resonant skew scattering is studied with first-principles band structure calculations. Especially the gigantic spin Hall angle $\gamma_S \cong 0.1$ observed recently (T.Seki et al., Nature Materials {\bf 7}, 125 (2008)) is attributed to the orbital-dependent Kondo effect of Fe in the Au host metal, where the $t_{2g}$-orbitals are in the mixed-valence region while $e_g$-orbitals are in the Kondo limit. The enhanced spin-orbit interaction by the electron correlation in the $t_{2g}$-orbitals leads to the gigantic spin Hall effect. Impurities with 5d orbitals are also discussed.