Clustering on Magnesium Surfaces - Formation and Diffusion Energies.

Area of Science:

• Materials Science
• Surface Science
• Computational Physics

Background:

• Atomic cluster formation and diffusion on metal surfaces are critical for understanding surface properties and material behavior.
• Surface roughness and faulted structures significantly influence the mechanical deformation of metals like magnesium (Mg).

Purpose of the Study:

• To investigate the formation and diffusion energies of atomic clusters on low-energy Mg surfaces using first-principles calculations.
• To analyze the impact of atomic clustering on surface structure and subsequent mechanical properties of Mg.

Main Methods:

• Density Functional Theory (DFT) based quantum mechanics calculations were employed for atomic clustering on Mg {0001} and [Formula: see text] surfaces.
• Molecular statics calculations were used to validate interatomic potentials and broaden the scope of DFT findings.

Main Results:

• On Mg {0001} surfaces, small clusters (<3 atoms) favor face-centered-cubic stacking, initiating stacking faults.
• On Mg [Formula: see text] surfaces, clusters of all sizes prefer hexagonal-close-packed stacking.
• Adatom diffusion is highly anisotropic on [Formula: see text] surfaces and isotropic on {0001} surfaces.

Conclusions:

• The stacking preferences of atomic clusters on Mg surfaces dictate the formation of surface structures and influence mechanical deformation.
• Understanding adatom diffusion mechanisms, including Ehrlich-Schwoebel barriers and step-edge diffusion, is crucial for controlling Mg surface properties.