Electron space charge effect on spin injection into semiconductors

TL;DR

This paper investigates how space charge effects influence spin injection and magnetoresistance in ferromagnet-insulator-semiconductor junctions, highlighting the importance of doping and interface resistance in optimizing spintronic device performance.

Contribution

It introduces a detailed analysis of space charge effects on spin transport, revealing conditions for enhanced magnetoresistance in semiconductor spintronic devices.

Findings

Spin current depends on spin configuration, doping, and space charge distribution.

Magnetoresistance ratio can be significantly increased with appropriate doping.

Space charge effects are crucial in nonequilibrium spin transport processes.

Abstract

We consider spin polarized transport in a ferromagnet-insulator/semiconductor/insulator-ferromagnet (F1-I-S-I-F2) junction. We find that the spin current is strongly dependent on the spin configurations, the doping and space charge distribution in the semiconductor. When the ferromagnet-semiconductor interface resistance is comparable to the semiconductor resistance, the magnetoresistance ratio of this junction can be greatly enhanced under appropriate doping when the space charge effect in the nonequilibrium transport processes is taken into consideration.