Prismatic dislocation loops in strained core-shell nanowire heterostructures

摘要

The formation of prismatic dislocation loops in a core nanowire coated with a thin shell has been investigated in the hypothesis where the core-shell interface is coherent leading to misft stress. In the framework of a thermodynamic equilibrium approach, the energy variation from the dislocation-free heterostructure has been calculated and the equilibrium positions of the loops have been determined as a function of the misfit stress, the nanowire radii, and the ratio of the shear modulus between the two phases. Depending on misft strain and radii, it is found that for a sufficiently soft core with respect to the shell, prismatic dislocation loops may form into the inner nanowire with equilibrium positions located at a few interatomic distances from the interface.