The static stress needed to de-pin a 2D edge dislocation, the lower dynamic stress needed to keep it moving, its velocity, and displacement vector profile were calculated from first principles. A simplified discrete model was used whose far-field distortion tensor decayed algebraically with distance; as in the usual elasticity. Dislocation de-pinning in the strongly over-damped case (including the effect of fluctuations) was analytically described. N parallel edge dislocations whose average interdislocation distance divided by the Burgers vector of a single dislocation was L » 1 could de-pin a given one if N = O(L). Then a limiting dislocation density could be defined and calculated in simple cases.

Edge Dislocations in Crystal Structures Considered as Traveling Waves in Discrete Models. A.Carpio, L.L.Bonilla: Physical Review Letters, 2003, 90[13], 135502 (4pp)