Surface structure of In₂O₃(111) (1 × 1) determined by density functional theory calculations and low energy electron diffraction

The surface structure of In₂O₃(111) has been investigated by dynamical analysis of low energy electron diffraction data, in conjunction with first principles calculations using density functional theory. The experimental data set consisted of eight independent beams whose intensities were measured for incident energies in the range between 25 eV and 250 eV. In fitting the experimental data it was essential to treat the radii of In and O spheres as variable parameters: following this procedure a final Pendry R factor of 0.31 was obtained. The LEED results are compatible with the calculations and both analyses suggest that the surface structure involves only small vertical relaxations in the outermost of the {[O^2-]₁₂ ^24-[In³⁺]₁₆⁴⁸⁺[O^2-] ₁₂^24-} quadrupolar units that define the (111) surface. The ab initio slab calculations also confirm that lateral relaxations not considered in fitting the experimental data are of very minor importance.