A total-energy pseudopotential simulation was made of the sliding process at  = 5 (001) twist grain boundaries. It was noted that sliding involved a stick-slip mechanism, with local re-bonding among a few atoms; accompanied by the clearance of gap states. At large strains, spreading of disorder from the boundary interface led to a loss of strength.

C.Molteni, G.P.Francis, M.C.Payne, V.Heine: Physical Review Letters, 1996, 76[8], 1284-7