The Surface Structure of V2O3(0001)
Vanadium oxides are widely used as catalysts in industrial reactions. The catalytic activity of a material depends on its surface structure. While the catalytic activity of V2O3(0001) has been shown before, the surface termination of V2O3(0001) films has been under debate since ion scattering experiments suggested that the surface is terminated by a trilayer of oxygen. This challenged the previously widespread view that the surface is terminated by a full layer of vanadyl groups. In this dissertation the surface structure of V2O3(0001) films was determined by combined I/V LEED and STM measurements to clear up this controversy. Analysis of numerous preparations show that the as prepared films are terminated by a full layer of vanadyl groups with some local defects. The vanadyl terminated surface can be oxidized to a partially vanadyl covered surface showing a 3x 3 R30* superstructure. Oxidation of the films showing a 3x 3 R30* superstructure leads to formation and evaporation of V2O5. These results were combined with concurring results by Jan Seifert et al. and Joachim Paier et al. obtained from fast atom diffraction and density functional theory calculations respectively. The surface structure of V2O3(0001) films reduced by electron bombardment was also characterized. These surfaces show a coexistence of two phases, a disordered and an ordered one. The ordered phase was shown to be terminated by a single layer of vanadium atoms on top of an oxygen trilayer.