Magnetite Fe3O4 (111) Surfaces: Impact of Defects on Structure, Stability, and Electronic Properties

We present a comprehensive investigation, via first-principles density functional theory (DFT) calculations, of various surface terminations of magnetite, Fe3O4 (111), a major iron oxide that also has a number of applications in electronics and spintronics. We compare the thermodynamic stability and electronic structure among the different surfaces terminations. Interestingly, we find that surfaces modified with point defects and adatoms are close in surface energy and that they can be more stable than bulk-like terminations in the oxygen-rich and -poor regimes. These surfaces show different surface chemistry and electronic structures as well as distinctive spin polarization features near the Fermi level with regard to those previously considered in the literature. Our studies provide an atomic level insight for magnetite surfaces, which is a necessary step to understanding their interfaces with organic layers in OLEDs and spintronic devices.