Versatile stochastic model for predictive KMC simulation of fcc metal nanostructure evolution with realistic kinetics

Area of Science:

• Materials Science
• Surface Science
• Computational Modeling

Background:

• Stochastic lattice-gas models are crucial for analyzing surface diffusion in crystalline metal nanostructures.
• Accurate modeling requires realistic prediction of atomic hopping rates across diverse surface environments.
• Existing generic barrier models often fail to capture complex diffusion behaviors.

Purpose of the Study:

• To introduce a novel Unconventional Interaction-Conventional Interaction formalism for prescribing surface diffusion barriers.
• To develop a more accurate and versatile model for simulating nanostructure evolution.
• To capture diverse diffusion phenomena, including terrace and step edge diffusion.

Main Methods:

• Utilizing kinetic Monte Carlo simulations with a rejection-free algorithm.
• Implementing the Unconventional Interaction-Conventional Interaction formalism to define diffusion barriers.
• Applying the model to single-component face-centered cubic (fcc) metal systems, primarily silver (Ag).

Main Results:

• The new formalism realistically captures key aspects of surface diffusion behavior with few parameters.
• The model successfully describes both 2D nanostructure reshaping and coalescence in thin films.
• It also accurately models the reshaping of 3D nanocrystals towards equilibrium Wulff shapes.

Conclusions:

• The Unconventional Interaction-Conventional Interaction formalism offers a significant improvement over generic barrier models.
• This versatile approach enhances the predictive power of lattice-gas models for nanostructure evolution.
• The method is applicable to various scenarios, including thin film growth and nanocrystal reshaping.