Simulations of surfaces and interfaces in MgO

Most simulations on surfaces and interfaces consider only the most symmetri c cases. However, it is far from clear that these interfaces are representa tive of the general interfaces seen in practice. For surfaces, the only cer amic systems to be studied are the stepped boundaries derived from surfaces vicinal to the (001) boundaries of MgO and NiO. We have performed an exten sive series of simulations to study the interfaces (both surfaces and grain boundaries) for magnesium oxide. The objective here is both to characteris e a variety of different kinds of steps on different surfaces and to relate these to the binding energies of grain boundaries. We use the simulations to discuss the general structure of grain boundaries and the adequacy of mo dels based on highly symmetric boundaries for discussing the properties of general boundaries.