Zhilenko T. Consideration of quasiequilibrium conditions of surface condensation of fractal structures

Сonditions that trend condensation/self-assembly process to steady state near phase equilibrium are analyzed. Fluctuations of both surface temperature and desorption flux are shown to play the role of multiplicative noise, which promote to transformation of the unimodal distribution of supersaturated component into the bimodal one. Phase portraits of the quasi equilibrium condensation process are investigated for different relations between relaxation times of deposed atom concentration, surface temperature and desorption flux. Only one steady-state is shown to be realized at small values of the equilibrium concentration and positive values of the accumulated flux. System evolution near this state is slowing-down or nonmonotonic to be dependent of characteristic relaxation times. Novel mechanism of new phase formation is studied both experimentally and theoretically on the example of quasi-equilibrium stationary condensation in ion-plasma sputterer. Copper condensates are obtained to demonstrate that in the course of deposition specific network structure is formed as a result of self-assembly. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. Time dependence of formation probability of branching structures is found to clarify the experimental situation.