On the structure of (111) twist grain boundaries in diamond: atomistic simulations with Tersoff-type interatomic potentials

In nanocrystalline diamond thin films, the high grain boundary density and the associated grain boundary properties may dominate the overall material behavior. In the present work, we systematically investigate (111) twist grain boundaries in diamond carbon by using atomistic simulations with Tersoff-type potential. Our work reveals the relation between atomic scale grain boundary structure and bicrystallography, bond deformation, point defect population. A comparative study with diamond silicon highlights general trends in the grain boundary energy as a function of the misorientation. We predict a transition between glide-plane grain boundary position and shuffle-plane grain boundary with increasing misorientation in diamond cubic materials with a (111) twist grain boundary.