Computer simulation of amorphous aluminum oxide structures by method of continuous static relaxation. 1

Structures of amorphous aluminum oxides were modeled by the method of continuous static relaxation with the use of two different potentials of aluminum interaction with oxygen depending on the aluminum coordination. The initial model consisted of an oxygen packing with an undistorted fcc lattice and cations statistically distributed over its voids. In the initial state, the Al-Al pairs can occupy two neighboring tetrahedra or a tetrahedron and neighboring octahedron. It is shown that relaxation due to Coulomb repulsion in this model results in considerable displacements of cations such that, at the final stage, no Al-Al pairs remain at all and the configuration becomes disordered. On the whole, the thus formed short-range order does not correspond to the atomic arrangement characteristic of thick Al2O3 amorphous films whose typical X-ray pattern is considered in this study. However, some elements of such ordering are also seen from the scattering patterns from barrier anodic oxide films