Properties of spatial arrangement of V-type defects in irradiated materials: 3D-modelling

We consider the dynamics of pattern formation in a system of point defects under sustained irradiation within the framework of the rate theory. In our study we generalize the standard approach taking into account a production of defects by elastic fields and a stochastic production representing internal multiplicative noise. Using 3D-modelling we have shown that with the damage rate growth, a morphology of clusters composed of vacancies changes. The same effect is observed with variation in the multiplicative noise intensity. Stationary patterns are studied by means of correlation analysis.Comment: 12 pages, 7 figure

Universality and self-similar behaviour of non-equilibrium systems with non-Fickian diffusion

Analytical approaches describing non-Fickian diffusion in complex systems are presented. The corresponding methods are applied to the study of statistical properties of pyramidal islands formation with interacting adsorbate at epitaxial growth. Using the generalized kinetic approach we consider universality, scaling dynamics and fractal properties of pyramidal islands growth. In the framework of generalized kinetics, we propose a theoretical model to examine the numerically obtained data for averaged islands size, the number of islands and the corresponding universal distribution over the island size.Comment: 10 pages, 6 figure

Colored noise influence on the system evolution

We present a picture of phase transitions of the system with colored multiplicative noise. Considering the noise amplitude as the power-law dependence of the stochastic variable $x^a$ we show the way to phase transitions disorder-order and order-disorder. The governed equations for the order parameter and one-time correlator are obtained and investigated in details. The long-time asymptotes in the disordered and ordered domains on the phase portrait of the system are defined.Comment: 12 pages, 8 figures, LaTeX. Submitted to EPJ-

Morphology change of the silicon surface induced by Ar+^+ ion beam sputtering

Two-level modeling for nanoscale pattern formation on silicon target by Ar$^+$ ion sputtering is presented. Phase diagram illustrating possible nanosize surface patterns is discussed. Scaling characteristics for the structure wavelength dependence versus incoming ion energy are defined. Growth and roughness exponents in different domains of the phase diagram are obtained.Comment: 11 pages, 5 figure

A study of phase separation processes in presence of dislocations in binary systems subjected to irradiation

Dislocation-assisted phase separation processes in binary systems subjected to irradiation effect are studied analytically and numerically. Irradiation is described by athermal atomic mixing in the form of ballistic flux with spatially correlated stochastic contribution. While studying the dynamics of domain size growth we have shown that the dislocation mechanism of phase decomposition delays the ordering processes. It is found that spatial correlations of the ballistic flux noise cause segregation of dislocation cores in the vicinity of interfaces effectively decreasing the interface width. A competition between regular and stochastic components of the ballistic flux is discussed.Comment: 22 pages, 11 figure