Eutectic crystallization and melting in sharp concentration gradients.

The initial stages of contact melting and eutectic crystallization in sharp concentration gradients between two crystalline components are studied and simulated analytically and numerically. Contact melting is shown to become possible only after the formation of some critical width of solid solutions. Crystallization in the sharp concentration gradient may lead to the formation of periodic structures in the interface vicinity.

Anisotropic Nucleation, Growth and Ripening under Stirring-A Phenomenological Model.

The anisotropic formation of elongated metal-oxide aggregates in water under intensive stirring is analyzed. It is treated in terms of anisotropic ballistically mediated aggregation kinetics in open systems. The basic kinetic equations describing the stages of homogeneous nucleation, independent growth, and ripening of the aggregates are formulated for the open system under the external influence with the stirring intensity as the main parameter governing the process.

Elementary models of the "flux driven anti-ripening" during nanobelt growth.

A stirring solution hydrothermal approach is widely used to rationally grow elongated oxide nanostructures with controllable aspect ratios. Depending on the synthesis conditions, the following are observed: (i) no nanostructure formation (the system exists as a pure liquid), (ii) formation of nanostructure starting from a critical powder/initial volume of the liquid solution, and (iii) monotonic increase in the nanostructure's aspect ratio (towards asymptotic value) with stirring rate. Despite these experimental observations, the theoretical understanding of the process is limited.

Phase competition in solid-state reactive diffusion revisited-Stochastic kinetic mean-field approach.

Kinetic mean-field method for description of diffusion (introduced in 1990 by George Martin) is developed to 3D with the inclusion of the frequency noise. After this, it is applied to modeling of reactive diffusion-formation, competition, and growth of the ordered intermediate phases during interdiffusion. Results seem reasonable; hence, the method can be used for qualitative study of complicated cases of the competitive first-order transitions in closed and open systems with rigid lattices.

Nucleation and atomic layer reaction in nickel silicide for defect-engineered Si nanochannels.

At the nanoscale, defects can significantly impact phase transformation processes and change materials properties. The material nickel silicide has been the industry standard electrical contact of silicon microelectronics for decades and is a rich platform for scientific innovation at the conjunction of materials and electronics. Its formation in nanoscale silicon devices that employ high levels of strain, intentional, and unintentional twins or grain boundaries can be dramatically different from the commonly conceived bulk processes.

Theory of repeating nucleation in point contact reactions between nanowires.

Modification of the classical Zeldovich nucleation theory for nonstationary conditions is presented. It is applied to the recently discovered repeating nucleation events in point contact reactions between metal and silicon nanowires to form epitaxial silicides; the nucleation provides the reproducible quasi-stationary conditions satisfying the fundamental suppositions of the modified theory. The modified theory enables us to predict the rate of repeating nucleation at nanoscale level by developing a theory of the incubation time.