2004 Volume 45 Issue 5 Pages 1461-1464
Relative stability between two types of reconstructed models of the {122} Σ = 9 coincidence boundary in cubic SiC has been examined by using the ab initio pseudopotential method based on the density-functional theory. Results are compared with the high-resolution transmission electron microscopy (HRTEM) observation in SiC polycrystalline films. A zigzag model consisting of zigzag arrangement of two sets of five- and seven-membered rings is more stable than a straight model consisting of straight arrangement of five-, six- and seven-membered rings, because of larger bond stretching in the latter model. The former model requires a rigid-body translation parallel to the interface. This may cause large strain at the triple junction with the {111} Σ = 3 boundaries, although this can be avoided by introducing a step at the junction. The HRTEM observation has clearly shown the presence of the zigzag model and the step at the triple junction.
