An extensive atomic resolution frequency modulation dynamic force microscopy study was made of ultra-thin aluminium oxide on a monocrystalline NiAl(110) surface. One-dimensional surface defects produced by domain boundaries were resolved. Images were presented for reflection domain boundaries (RDBs), four different types of antiphase domain boundaries, a nucleation-related translation domain boundary and also domain boundary junctions. New structures and aspects of the boundaries and their network were revealed and merged into a comprehensive picture of the defect arrangements. The alumina film also covers the substrate completely at the boundaries and their junctions and follows the structural building principles found in its unit cell. This encompasses square and rectangular groups of surface oxygen sites. The observed structural elements can be related to the electronic signature of the boundaries and therefore to the electronic defects associated with the boundaries. A coincidence site lattice predicted for the RDBs was in good agreement with experimental data. With Σ = 19 it can be considered to be of low-sigma type, which frequently coincides with special boundary properties. Images of asymmetric RDBs show points of good contact alternating with regions of nearly amorphous disorder in the oxygen sublattice.

Atomic Structure of Surface Defects in Alumina Studied by Dynamic Force Microscopy - Strain-Relief-, Translation- and Reflection-Related Boundaries, Including their Junctions. G.H.Simon, T.König, L.Heinke, L.Lichtenstein, M.Heyde, H.J.Freund: New Journal of Physics, 2011, 13[12], 123028