The chemical pathways leading to L12 nucleation from nondilute Ni-5.2 Al-14.2 Cr at. %, fcc , at 873 K are followed with radial distribution functions and isoconcentration surface analyses of direct-space atom-probe tomographic images. Although Cr atoms initially are randomly distributed, a distribution of congruent Ni3Al short-range-order domains SRO , R 0.6 nm, results from Al diffusion durin...

In this work, we report on the electroplating of ultrafine and uniform magnesium (Mg) films on copper (Cu) and carbon nanotube (CNT) paper substrates. By controlling the process parameters and utilizing the pulsed deposition method, the average grain size of Mg was reduced to nanodimensions. Surface pretreatment of the substrates by depositing a seed layer was found to be an efficient strategy ...

The interplay between electric field-controlled surface magnetic anisotropy and micromagnetic nucleation modes for L10-CoPt thin films is investigated with density-functional and micromagnetic model calculations. The electric field redistributes electron states near the Fermi level, which has a fairly strong effect on the surface anisotropy, but due to inversion symmetry, the net anisotropy of ...

We have applied density functional methods to predict the nucleation rates of bubbles in superheated, stretched, or supersaturated binary fluid mixtures. Our model uses Lennard-Jones mixtures, with mixing rules chosen to allow either ideal or nonideal solution behavior. Deviations from the predictions of classical nucleation theory are in general quite large, with the locus of observable bubble...

We present hard-sphere crystallization kinetics for three samples with small differences in polydispersity. We show that an increase in polydispersity of 1% is sufficient to cause dramatic changes in the crystallization kinetics: crystallization is delayed by almost one decade in time and quantitative and qualitative changes in the crystallization scenario are observed. Surprisingly the nucleat...

The space subdivision in cells resulting from a process of random nucleation and growth is a subject of interest in many scientific fields. In this paper, we deduce the expected value and variance of these distributions while assuming that the space subdivision process is in accordance with the premises of the KolmogorovJohnson-Mehl-Avrami model. We have not imposed restrictions on the time dep...

We describe a theoretical study of the role of adsorbate interactions in island nucleation and growth, using Ag/Pt(111) heteroepitaxy as an example. From density-functional theory, we obtain the substrate-mediated Ag adatom pair interaction and we find that, past the short range, a repulsive ring is formed about the adatoms. The magnitude of the repulsion is comparable to the diffusion barrier....

We introduce a comprehensive quantitative treatment for burst nucleation (BN)-a kinetic pathway toward self-assembly or crystallization defined by an extended post-supersaturation induction period, followed by a burst of nucleation, and finally the growth of existing stable assemblages absent the formation of new ones-based on a hybrid mean field rate equation model incorporating thermodynamic ...

The heteroepitaxial growth of gallium nitride (GaN) on sapphire substrates by metal-organic chemical vapor deposition is most commonly carried out using the two-step growth process. This process involves the deposition of a thin GaN nucleation layer (NL) at a temperature of approximately 450–600 1C. The morphology of this low-temperature film after annealing is known to have a crucial effect on...

We compute the probability distribution of the invariant separation between nucleation centers of colliding true vacuum bubbles arising from the decay of a false de Sitter space vacuum. We find that even in the limit of a very small nucleation rate (ΓH−5 ≪ 1) the production of widely separated bubble pairs is suppressed. This distribution is of particular relevance for the recently proposed “co...