An atomistic model was proposed, for describing the Cu/sapphire interface, by using simple interatomic potentials that involved only a few fitting parameters. Good results were obtained when the Cu atoms in the monatomic layer closest to the interface had properties which were different to those of the bulk. This layer reconciled the ionic/covalent bonding of the ceramic with the metallic bonding of Cu. For an O-terminated interface, the parameters of the potentials were fitted to the results of a rigid tensile test; simulated from first principles. The results of atomic relaxation near to the interface were shown to be consistent with published ab initio and experimental results. The calculations revealed very interesting relaxation dynamics which occurred near to the interface. In the early stages of relaxation, a periodic network of partial misfit dislocations formed and later transformed into an irregular network; due to the instability of the layer of Cu atoms on top of the O atoms. This explained an interface incoherency which was observed in high-resolution electron microscopy, and calculations which were based upon the F-K model reproduced this effect.

Atomistic Structure of the Cu(111)/α-Al2O3(0001) Interface in Terms of Interatomic Potentials Fitted to ab initio Results. S.V.Dmitriev, N.Yoshikawa, M.Kohyama, S.Tanaka, R.Yang, Y.Kagawa: Acta Materialia, 2004, 52[7], 1959-70