  The morphology transition from the thermodynamically favorable to the
unfavorable phase during growth of free-standing copper nanoclusters is studied
by molecular dynamics simulations. We give a detailed description of the
kinetics and thermodynamics of the process. A universal mechanism of a
solid-solid transition, from icosahedral to decahedral morphology in
nanoclusters, is proposed. We show that a formation of distorted NC during the
growth process with islands of incoming atoms localized in certain parts of the
grown particle may shift the energy balance between Ih and Dh phases in favour
of the latter leading to the morphology transition deep within the
thermodynamic stability field of the former. The role of diffusion in the
morphology transition is revealed. In particular, it is shown that fast
diffusion should suppress the morphology transition and favour homogeneous
growth of the nanoclusters.
