THE ENTROPY BARRIER AND THE RATE OF DIFFUSION-STRAIN NUCLEATION OF CLUSTERS OF POINT-DEFECTS IN LASER-IRRADIATED SOLIDS

Using the diffusion-strain model, we calculate the nucleation rate of clusters of nonequilibrium point defects with allowance for the entrop y barrier. It is demonstrated that cluster nucleation begins only when the initial fluctuation of the concentration of defects exceeds a cri tical value. A nonmonotonic (extremal) dependence of the nucleation ra te on the concentration of point defects is obtained. We establish an analogy between temperature dependences of the rate of nonequilibrium cluster nucleation and the rate of nucleation of the crystalline phase in equilibrium crystallization of amorphous media.