Determination of Interface Atomic Structure and Its Impact on Spin Transport Using Z-Contrast Microscopy and Density-Functional Theory

TL;DR

This study combines microscopy and theoretical calculations to analyze the atomic structure of the Fe/AlGaAs interface, revealing how interface quality affects spin-injection efficiency in light-emitting diodes.

Contribution

It provides a detailed atomic-level understanding of the interface structure and its direct impact on spin transport, integrating experimental and computational methods.

Findings

44% increase in spin-injection efficiency after annealing

Ordered interface with single atomic plane of Fe and As

Increased efficiency linked to interface abruptness and coherence

Abstract

We combine Z-contrast scanning transmission electron microscopy with density-functional-theory calculations to determine the atomic structure of the Fe/AlGaAs interface in spin-polarized light-emitting diodes. A 44% increase in spin-injection efficiency occurs after a low-temperature anneal, which produces an ordered, coherent interface consisting of a single atomic plane of alternating Fe and As atoms. First-principles transport calculations indicate that the increase in spin-injection efficiency is due to the abruptness and coherency of the annealed interface.