829 research outputs found
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 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
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