Coherency of copper/sapphire interface studied by atomistic simulation and geometrical analysis

From experiment it is known that, for copper epitaxially grown on α-Al2O3(0 0 0 1) surface, the close-packed planes and the close-packed directions are parallel in the two crystals. In this work, we present the results of computer simulations based on a simple atomistic model assuming that sapphire is absolutely rigid. For the Cu–Cu interactions, both the Morse pair potential and the Rosato–Guillope–Legrand many-body potential were used. The interaction of copper with sapphire was described by means of the copper potential functions modified by introducing the two fitting parameters. We introduce a measure of the atomic coherency near the interface and study the change in coherency due to atomic relaxations. Results for the two mutual orientations are compared. Finally, using a method recently proposed by the present authors, we study coherency of interpenetrating copper and sapphire crystals as a function of the misorientation angle.