By using an atomistic model, a study was made of misfit accommodation at the Cu(111)/ α-Al2O3(00▪1) interface having the orientation relationship: <¯101>Cu||<1¯1▪0>Al2O3. Well-known interatomic potentials for bulk Cu and sapphire were used, and an attempt was made to describe interactions across the interface by using simple pair potentials having a few fitting parameters. A degree of coherency which was sensitive to atomic relaxations near to the interface was also introduced. Misfit dislocation networks, changes in coherency near to the interface due to atomic relaxations, and the interface energies calculated for various magnitudes of the potential fitting parameters were compared. The results were quite sensitive to the interatomic potentials which were used for Cu. A Morse pair-wise potential gave a low energy for the stacking fault, and the misfit dislocations dissociated into partials. A more realistic many-body potential resulted in a higher energy for the stacking fault, and dislocation dissociation was suppressed. Moreover, the misfit dislocation network found with the Morse potential was unstable when interaction across the interface was rather strong. The instability effect disappeared in frame of the many-body potential which, unlike the Morse potential, reproduces the elastic moduli and the anisotropic constant of Cu.

Misfit Accommodation at the Cu(111)/α-Al2O3(0001) Interface Studied by Atomistic Simulation. S.V.Dmitriev, N.Yoshikawa, Y.Kagawa: Computational Materials Science, 2004, 29[1], 95-102