Enhanced Spin Hall Effect by Resonant Skew Scattering in the Orbital-Dependent Kondo Effect

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 Mater. 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.

Figure 1

The spin polarization $S(\theta )\overrightarrow{n}$ induced by the skew scattering due to the spin-orbit interaction of the scatterer and the spin unpolarized electron beam.

Figure 2

Total, site-, orbital- and spin-decomposed DOSs of (a) bulk fcc Au, 3.1% Au-vacancies, (b) 3.1% Pt impurities, (c) 3.1% Fe impurities in nonmagnetic state, and (d) in ferromagnetic state.

Figure 3

Site-decomposed DOSs and phase shifts ($\delta$) of (a) 3.1% W and (b) 3.1% Os in Au.