Mounding instability and incoherent surface kinetics

Area of Science:

• Surface science
• Materials science
• Condensed matter physics

Background:

• Conserved growth from vapor often exhibits mounding instability.
• Understanding adatom kinetics is crucial for controlling surface morphology.

Purpose of the Study:

• To analyze mounding instability within the framework of adatom kinetics.
• To investigate the influence of local surface structure on adatom behavior.

Main Methods:

• Theoretical analysis of adatom kinetics on a growing surface.
• Continuum description considering disjoint regions based on local structure.
• Dimensional analysis for (1+1) and (2+1) growth dimensions.
• Computational simulations to validate theoretical predictions.

Main Results:

• Adatom kinetics vary with local surface structure, creating disjoint regions.
• Mounding instability is particularly pronounced under these conditions.
• Lateral mound growth is governed by downward adatom flux across steps.
• A logarithmic dependence on time (ln t) is predicted and observed in (1+1) dimensions.

Conclusions:

• Local surface structure significantly impacts adatom kinetics and growth instability.
• The proposed model accurately predicts mound growth behavior.
• Further discussion on growth dynamics in (2+1) dimensions is provided.