# Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

## TL;DR

This study investigates how doping density and indium concentration affect current-induced spin polarization in InGaAs and GaAs epilayers, revealing the roles of extrinsic mechanisms and providing theoretical insights.

## Contribution

It introduces a comprehensive model including extrinsic effects to explain spin polarization phenomena in doped semiconductor epilayers, supported by experimental validation.

## Key findings

- Higher indium and carrier concentrations increase spin generation efficiency.
- Spin polarization observed in GaAs without measurable spin-orbit fields.
- Theoretical model including extrinsic effects aligns qualitatively with experiments.

## Abstract

The current-induced spin polarization and momentum-dependent spin-orbit field were measured in In$_{x}$Ga$_{1-x}$As epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to qualitatively agree with the experimental results.