Theory of Spin Hall Effect in Random Pt–M (M = V, Nb, Ta) Alloys

Abstract

The spin Hall effect in fcc Pt-rich disordered solid solutions Pt–M (M = V, Nb, Ta) is studied by means of a relativistic ab initio Green-function theory. We find that the spin Hall angle of all three alloy systems exhibits similar sizable values, with a maximum slightly above 0.2, obtained for dopant concentrations around 12 at.%. This result is explained by a competition between opposite concentration trends of the intrinsic spin Hall conductivity and of the longitudinal residual resistivity while the strength of the impurity spin–orbit interaction plays only a minor role. This behavior agrees qualitatively with results of recent experiments on spin Hall torques in multilayered systems involving Pt-rich alloys with heavy and light impurities.