On the mechanism of the electric field effect on dislocation mobility in alkali-halide crystals

The dependence is investigated of the velocity of motion of edge and screw dislocations on the applied shear stress in annealed and quenched NaCl and KC1 crystals with various impurity content under the action of an electric field of up to 50 kV/cm. It is shown that in impure crystals the action of the field is determined by its effect on damping centers, while in pure crystals, by its effect on charged dislocations. The interaction force of an edge dislocation with “impurity-vacancy” dipoles of various orientation is calculated. The charge density and sign of a dislocation is estimated.