Quantum-size effect and tunneling magnetoresistance in ferromagnetic-semiconductor quantum heterostructures

TL;DR

This paper investigates how quantum-size effects influence tunneling magnetoresistance in ferromagnetic-semiconductor heterostructures, revealing resonant tunneling phenomena and the importance of Fermi level positioning.

Contribution

It demonstrates the observation of resonant tunneling and its enhancement of TMR in GaMnAs quantum wells, explained by a valence-band kp model including p-d exchange.

Findings

Resonant tunneling enhances TMR in GaMnAs heterostructures.

Quantum levels are explained by a valence-band kp model with p-d exchange.

Fermi level position is crucial for observing resonant tunneling.

Abstract

We report on the resonant tunneling effect and the increase of tunneling magnetoresistance (TMR) induced by it in ferromagnetic-semiconductor GaMnAs quantum-well heterostructures. The observed quantum levels of the GaMnAs quantum well were successfully explained by the valence-band kp model with the p-d exchange interaction. It was also found that the Fermi level of the electrode injecting carriers is important to observe resonant tunneling in this system.