Manipulation of the sign of the spin Hall effect using Cu alloys doped with 5d elements

5d要素がドープされたCu合金を用いたスピンホール効果の符号の操作

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

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

The spin Hall effect, which converts the injected longitudinal charge current into the transverse spin current via the spin-orbit interaction, is crucial for the development of spintronic devices. The sign of the spin Hall angle (SHA) describes the direction of the induced transverse current. A positive SHA of 2.1% was observed experimentally in the CuIr alloys. Our calculations showed that local correlation effects of the 5d orbitals of Ir impurities correct the electron distribution among different orbitals, which can explain the positive sign of SHA in physical terms. This also opens up a way to control the sign of SHA by manipulating the local correlation strength or the electron occupation number of the impurities. We therefore checked different 5d elements as impurities in the Cu alloys, and predicted candidates other than CuIr alloys as potential switches of the sign of the SHA.