The equilibrium atomic structure of the (101) and (301) twin boundaries in rutile was computed using an ionic shell model and compared with high resolution electron microscopy images of the same boundaries using image simulation. The lowest-energy (101) twin boundary structure was characterized by an in-plane translation of ½<111> which conserved the mirror symmetry of the metal sub-lattice but which imposes a displacement on the oxygen sublattice. The lowest-energy (301) twin-boundary structure involves no in-plane translation and was characterized by mirror symmetry of both the metal and the oxygen sub-lattices. The computed mirror symmetry of the metal sublattice for both twin boundaries was in agreement with the electron microscopy observations. A small distortion present in the simulated images was explained in terms of the interatomic potential used in the calculations.

The Atomic Structure of Twin Boundaries in Rutile. Lee, W.Y., Bristowe, P.D., Gao, Y., Merkle, K.L.: Philosophical Magazine Letters, 1993, 68[5], 309-14