Sign change of the spin Hall effect due to electron correlation in nonmagnetic CuIr alloys

非磁性CuIr合金におけるスピンホール効果の電子相関による符号変化

Xu, Z.; Gu, B.; 森 道康  ; Ziman, T.*; 前川 禎通

Xu, Z.; Gu, B.; Mori, Michiyasu; Ziman, T.*; Maekawa, Sadamichi

Recently a positive spin Hall angle (SHA) of 0.021, was observed experimentally in nonmagnetic CuIr alloys and attributed predominantly to an extrinsic skew scattering mechanism, while a negative SHA was obtained from ab initio calculations, using consistent definitions of the SHA. We reconsider the SHA in CuIr alloys, with the effects of the local electron correlation U in 5d orbitals of Ir impurities, included by the quantum Monte Carlo method. We found that the SHA is negative if we ignore such local electron correlation, but becomes positive once U approaches a realistic value. This may open up a way to control the sign of the SHA by manipulating the occupation number of impurities.