Axial misfit stress relaxation in core–shell nanowires with polyhedral cores through the nucleation of misfit prismatic dislocation loops

Abstract

The theoretical model of axial misfit stress relaxation in polyhedral core–shell nanowires through the nucleation of prismatic dislocation loops is suggested. Different sites of dislocation nucleation in the nanowires with hexagonal, square and triangular shapes of the core cross section are considered. The energy change caused by the dislocation nucleation is calculated for every case under the assumption that the shell thickness is much smaller than the core size. The corresponding critical values of the misfit parameter for the dislocation nucleation are determined and compared with each other. According to this comparison, the most favorable sites in the core–shell nanowires and the optimal shapes of the dislocation loops are defined. Nanowires with round, hexagonal, square and triangle shapes of the core cross section are ranged with respect to their stability to dislocation loop nucleation.