Temperature dependence of the flow stress of III–V compounds

Abstract

An interpretation for the temperature dependence of the plastic flow stress of III–V compounds is presented, invoking only non-dissociated screw dislocations. With the aid of the Stillinger-Weber potential for the interatomic interaction, the Peierls potential of a non-dissociated screw dislocation is deduced in twodimensional space normal to the dislocation line. A saddle-point configuration and the formation energy of a kink pair are calculated in three-dimensional space. The relation obtained between the flow stress T _c and temperature T under a constant strain rate describes the experimental T _c−T relation of III–V compound well: a strong T dependence at highT _c and low T, a stronger T dependence at low Tc and high T, and a plateau-like T _c at intermediate T. The hump in the T _c−T relation is interpreted as a transition between different paths of the non-dissociated screw dislocation: a planar path and a zigzag path in the (111) plane.