title: Sign change of the spin Hall effect due to electron correlation in nonmagnetic CuIr alloys.
abstract: Recently, a positive spin Hall angle (SHA) of 0.021 was observed experimentally in nonmagnetic CuIr alloys [Niimi et al, Phys. Rev. Lett. 106, 126601 (2011)] and attributed predominantly to an extrinsic skew scattering mechanism, while a negative SHA was obtained from ab initio calculations [Fedorov et al, Phys. Rev. B 88, 085116 (2013)], 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.
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan.
authors.forename: Bo
authors.initials: B
authors.lastname: Gu
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan.
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Mori
authors.affiliation: Institut Laue Langevin, Boîte Postale 156, F-38042 Grenobel Cedex 9, France and LPMMC (UMR 5493), Université Grenoble 1 and CNRS, 38042 Grenoble, France.
authors.forename: Timothy
authors.initials: T
authors.lastname: Ziman
authors.affiliation: Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan.
authors.forename: Sadamichi
authors.initials: S
authors.lastname: Maekawa