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.
@article{arxiv.cond-mat/0605202,
title = {Determination of Interface Atomic Structure and Its Impact on Spin Transport Using Z-Contrast Microscopy and Density-Functional Theory},
author = {Thomas J. Zega and Aubrey T. Hanbicki and Steven C. Erwin and Igor Zutic and George Kioseoglou and Connie H. Li and Berend T. Jonker and Rhonda M. Stroud},
journal= {arXiv preprint arXiv:cond-mat/0605202},
year = {2007}
}