题 目：Spin Hall Effect Induced by Resonant Scattering on Impurities in Metals
报告人：Prof. Peter M. Levy （New York University, Department of Physics）
The origins of the Spin Hall Effect (SHE) are the same as those that have produced the Anomalous Hall Effect (AHE) which has been known for over 6-7 decades. The AHE is caused by ordinary charge currents in a magnetic field or a magnetic metal, and produces additional contributions to the ordinary Hall Effect. It is caused by spin-orbit coupling effects on the band structure, defect scattering, and on the expression for the electric current (anomalous velocity or side jump). The SHE is caused by the same mechanisms but relies on the presence of a spin-polarized current.
The SHE is a promising way for transforming charge currents into spin currents in spintronic devices. Large values of the Spin Hall Angle, the characteristic parameter of the yield of this transformation, have been recently found in noble metals doped with nonmagnetic impurities. We show that this can be explained by resonant scattering off impurity states split by the spin-orbit interaction. We apply our calculation to the interpretation of experiments on copper doped with 5d impurities and we describe the conditions to obtain the largest effects.