First-principles investigations of the structural, electronic and magnetic properties of Cr-doped AlN/GaN (0001) heterostructures reveal that Cr segregates into the GaN region, that these interfaces retain their important half-metallic character and thus yield efficient (100 %) spin polarized injection from a ferromagnetic GaN:Cr electrode through an AlN tunnel barrier - whose height and width can be controlled by adjusting the Al concentration in the graded bandgap engineered Al(1-x)Ga(x)N (0001) layers.
@article{arxiv.cond-mat/0410455,
title = {Half-metallicity and efficient spin injection in AlN/GaN:Cr (0001) heterostructure},
author = {J. E. Medvedeva and A. J. Freeman and X. Y. Cui and C. Stampfl and N. Newman},
journal= {arXiv preprint arXiv:cond-mat/0410455},
year = {2009}
}