Mg(0001) surface oxidation:: A two-dimensional oxide phase -: art. no. 193405

First-principles electronic structure calculations and angle-scanned x-ray photoelectron diffraction experiments reveal the geometrical structure of the Mg(0001) surface upon oxidation. In contrast to previous studies of Mg(0001) oxidation and unlike the case of aluminum oxidation we determine a surface oxide structure, consisting of mixed oxygen-magnesium layers on top of an almost unchanged Mg(0001) surface. This unusual, directionally bound, surface oxide is locally formed already at very low dosing, corresponding to total coverages of 0.1 monolayer (ML), and grows laterally with increasing oxygen coverage up to at least 3 ML total coverage.