All-electrical measurements of direct spin Hall effect in GaAs with Esaki diode electrodes

Abstract

We report on measurements of direct spin Hall effect in a lightly $n$-doped GaAs channel with conductivity below 2000 \ensuremath{\Omega}${}^{\ensuremath{-}1}$ m${}^{\ensuremath{-}1}$. As spin detecting contacts, we employed highly efficient ferromagnetic Fe/(Ga,Mn)As/GaAs Esaki diode structures. We investigate bias and temperature dependence of the measured spin Hall signal and evaluate the value of total spin Hall conductivity and its dependence on channel conductivity and temperature. From the results, we determine skew scattering and side-jump contribution to the total spin Hall conductivity and compare it with the results of experiments on higher conductive $n$-GaAs channels [Garlid, Hu, Chan, Palmstr\o{}m, and Crowell, Phys. Rev. Lett. 105, 156602 (2010)]. As a result, we conclude that both skewness and side jump contribution cannot be treated as fully independent of the conductivity of the channel.