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Many body effects in electronic dynamics and transport

Many body effects in electronic dynamics and transport. F SO. J. J s. F SO. Spin Hall Effect: the regular current (J) drives a spin current (J s ) across the bar resulting in a spin accumulation at the edges. Skew scattering.

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Many body effects in electronic dynamics and transport

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  1. Many body effects in electronic dynamics and transport FSO J Js FSO Spin Hall Effect: the regular current (J) drives a spin current (Js) across the bar resulting in a spin accumulation at the edges. Skew scattering More spin up electrons are deflected to the right than to the left (and viceversa for spin down) e impurity Side Jump e For a given deflection, spin up and spin down electrons make a side-jump in opposite directions. Giovanni Vignale, University of Missouri-Columbia,DMR-0313681 Electron-electron interaction in the Spin Hall Effect The Spin Hall Effect is the generation of a lateral spin current from a regular electric current. It attracts great interest as a method to separate electrons of opposite spin by purely electrical means (see Figure). The main driving mechanism for the Spin Hall Effect is the scattering of electrons by impurities in the presence of spin-orbit interaction. The figure shows the two main processes through which impurities separate the spins: they are known as skew scattering and side jump. In addition, the magnitude of the spin current is strongly influenced by the Coulomb interaction between the electrons. When electrons of opposite spin travel in opposite directions they exert a force on each other, tending to reduce the relative motion. This is the phenomenon of the spin Coulomb drag and we have studied its impact on the Spin Hall Effect.

  2. How to distinguish different contributions to the spin Hall effect no drag drag temperature [K] E. Hankiewicz and G. Vignale, Phys. Rev. B 73, 115339 (2006) E. Hankiewicz and G. Vignale and M. Flatte’, cond-mat/0603144 Spin Coulomb Drag Our results are summarized in the top figure on the right. We found that the spin Coulomb drag reduces the skew-scattering contribution. The contributions with and without Coulomb drag are shown by the dotted and the dashed green lines respectively. The side-jump contribution (blue dashed line) remains unaffected. The figure also shows the typical magnitude of the two contributions at different temperatures in a clean GaAs spin Hall bar. A crucial experiment We propose an experiment to distinguish the skew-scattering and side-jump contributions. We observe that the side jump and the skew scattering have opposite signs. But the side jump is independent of temperature while the skew scattering is directly proportional to the electronic mobility - a measure of how fast the electron can drift in an electric field - which in turn is strongly dependent on temperature (green circles on the right). Hence we expect a transition from a skew-scattering-dominated to a side-jump-dominated regime as the temperature is reduced. A change in sign of the spin accumulation will reveal the transition.

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