Determination of Interface Atomic Structure and Its Impact on Spin   Transport Using Z-Contrast Microscopy and Density-Functional Theory
  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. 
Thomas J. Zega, Aubrey T. Hanbicki, Steven C. Erwin, Igor Zutic,   George Kioseoglou, Connie H. Li, Berend T. Jonker, and Rh...