Enhanced spin Hall effect in strong magnetic disorder

TL;DR

This paper studies how strong magnetic disorder affects spin-dependent transport in a 2D electron gas, revealing a localization transition, fractal states, and enhanced spin currents in the strong disorder regime.

Contribution

It demonstrates the impact of magnetic disorder on wave-function localization, spin polarization, and spin current enhancement in a 2D electron system, linking geometrical properties to transport behavior.

Findings

Localization transition with fractal states

Power-law diffusion behavior below transition

Enhanced spin current in strong disorder regime

Abstract

We consider a two-dimensional electron gas in an inversion asymmetric layer and in the presence of spatially distributed magnetic impurities. We investigate the relationship between the geometrical properties of the wave-function and the system's spin dependent transport properties. A localization transition, arising when disorder is increased, is exhibited by the appearance of a fractal state with finite inverse participation ratio. Below the transition, interference effects modify the carrier's diffusion, as revealed by the dependence on the scattering time of the power law exponents characterizing the spreading of a wave packet. Above the transition, in the strong disorder regime, we find that the states are spin polarized and localized around the impurities. A significant enhancement of the spin current develops in this regime.