Tight-binding molecular dynamics simulations of a typical high-energy grain boundary showed that its equilibrium atomic structure was similar to that of bulk amorphous material, and that it contained coordination defects. The corresponding electronic structure was also amorphous-like, and exhibited gap states that were localized mainly around the coordination defects; where large changes in the bond-hybridization character were observed. It was suggested that such coordination defects, in disordered high-energy grain boundaries, were responsible for experimentally observed gap states in polycrystalline Si.

F.Cleri, P.Keblinski, L.Colombo, S.R.Phillpot, D.Wolf: Physical Review B, 1998, 57[11], 6247-50