Spin-Polarized Hot Electron Injection into Two-Dimensional Electron Gas by Magnetic Tunnel Transistor

Abstract

A magnetic tunnel transistor has been fabricated on top of a modulation-doped GaAs/AlGaAs heterostructure that provides a high-mobility two-dimensional electron gas. The emitter and base of the magnetic tunnel transistor consisted of a ferromagnetic metal, whereas the collector consisted of the two-dimensional electron gas. Spin polarized hot electrons from the emitter were filtered by the CoFe base layer and then injected into the collector, leading to a finite magnetocurrent ratio. The magnetocurrent ratio decreased as the hot electron energy was increased by increasing the bias voltage between the emitter and the base above a certain threshold voltage. We observed magnetocurrent ratios of ∼27% at 17 K and ∼2% at 300 K, indicating that spin-polarized hot electrons are injected into the two-dimensional electron gas from 17 K up to room temperature.