Xu Zhuo, Gu Bo, Mori Michiyasu, Ziman Timothy, Maekawa Sadamichi
Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075, Japan.
Institut Laue Langevin, Boîte Postale 156, F-38042 Grenobel Cedex 9, France and LPMMC (UMR 5493), Université Grenoble 1 and CNRS, 38042 Grenoble, France.
Phys Rev Lett. 2015 Jan 9;114(1):017202. doi: 10.1103/PhysRevLett.114.017202. Epub 2015 Jan 6.
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.
最近，在非磁性CuIr合金中通过实验观测到了0.021的正自旋霍尔角（SHA）[新见等人，《物理评论快报》106, 126601 (2011)]，其主要归因于一种外在的斜散射机制，而使用一致的SHA定义，从第一性原理计算中得到了一个负的SHA [费多罗夫等人，《物理评论B》88, 085116 (2013)]。我们重新考虑CuIr合金中的SHA，通过量子蒙特卡罗方法纳入Ir杂质5d轨道中局域电子关联U的影响。我们发现，如果忽略这种局域电子关联，SHA为负，但一旦U接近实际值，SHA就会变为正。这可能为通过操纵杂质的占据数来控制SHA的符号开辟一条途径。
