Mechanics of structural degradation in composite nanoparticles

This article features different mechanisms of structural degradation, which can accompany the fabrication of composite nanoparticles, and some attempts of their theoretical description. Special attention is paid to various channels of misfit strain release in spherically symmetric core–shell nanoparticle. It is demonstrated that accurate use of continuum mechanics allows to calculate the critical conditions that are necessary for generation of various misfit defects among which the misfit dislocations are the most energetically preferable. In particular, the critical conditions for the formation of a prismatic loop of misfit dislocation around the core are discussed in detail. Some preliminary results of theoretical modeling of rectangular prismatic misfit dislocation loops in the shell of a core–shell nanoparticle are also briefly reported. The general conclusion is made that there are still many other types of composite nanoparticles and possible channels of their structural relaxation/degradation, which are worth of studying.