Nonlinear anomalous Hall effect and negative magnetoresistance in a system with random Rashba field

TL;DR

This paper predicts novel spin-dependent transport phenomena in 2D electron systems caused by random Rashba spin-orbit interactions, including a nonlinear anomalous Hall effect and negative magnetoresistance.

Contribution

It introduces the prediction of nonlinear anomalous Hall effect and negative magnetoresistance induced by spatially fluctuating Rashba fields in 2D systems, a novel theoretical insight.

Findings

Anomalous Hall conductivity depends nonlinearly on magnetization, decreasing exponentially at high spin densities.

Negative magnetoresistance arises from spin-dependent scattering in nonmagnetic 2D systems due to Rashba fluctuations.

The phenomena are demonstrated in systems like magnetic semiconductor quantum wells.

Abstract

We predict two spin-dependent transport phenomena in two-dimensional electron systems, which are induced by spatially fluctuating Rashba spin-orbit interaction. When the electron gas is magnetized, the random Rashba interaction leads to the anomalous Hall effect. An example of such a system is a narrow-gap magnetic semiconductor-based symmetric quantum well. We show that the anomalous Hall conductivity reveals a strongly nonlinear dependence on the magnetization, decreasing exponentially at large spin density. We also show that electron scattering from a fluctuating Rashba field in a two-dimensional nonmagnetic electron system leads to a negative magnetoresistance arising solely due to spin-dependent effects.