Mounding Instability and Incoherent Surface Kinetics

TL;DR

This paper analyzes the mounding instability in vapor-grown surfaces, showing how local surface structure affects adatom kinetics, leading to disjoint growth regions and specific growth dynamics confirmed by simulations.

Contribution

It introduces a framework linking surface structure to adatom kinetics, revealing disjoint growth regions and asymptotic growth behavior in different dimensions.

Findings

Disjoint regions form during instability due to local surface structure variations.

Lateral mound growth is driven by adatom flux across steps.

ln(t) growth dependence is confirmed in 1+1 dimensions.

Abstract

Mounding instability in a conserved growth from vapor is analysed within the framework of adatom kinetics on the growing surface. The analysis shows that depending on the local structure on the surface, kinetics of adatoms may vary, leading to disjoint regions in the sense of a continuum description. This is manifested particularly under the conditions of instability. Mounds grow on these disjoint regions and their lateral growth is governed by the flux of adatoms hopping across the steps in the downward direction. Asymptotically ln(t) dependence is expected in 1+1- dimensions. Simulation results confirm the prediction. Growth in 2+1- dimensions is also discussed.