From Atomic Scale Ordering to Mesoscale Spatial Patterns in Surface Reactions: Heterogeneous Coupled Lattice-Gas (HCLG) Simulation Approach

Thursday, April 14, 2005 - 2:30pm - 3:30pm
EE/CS 3-180
James Evans (Iowa State University)
Homoepitaxial thin film growth produces a rich variety of far-from-equilibrium morphologies. Atomistic lattice-gas models analyzed by KMC simulation have been most successful to date in predicting behavior observed in specific experiments.

However, 2D continuum formulations (level-set, phase-field, geometry-based-simulation = GBS) retaining discrete layers have been explored as alternatives, especially for the regime of highly reversible island formation where KMC becomes inefficient. Exploiting GBS, we present the first precise results for the submonolayer island size distribution in this regime [1].

3D continuum formulations have been applied to describe multilayer kinetic roughening where step edge barriers inhibit downward transport and produce unstable growth (mound formation). We analyze this phenomonon using realistic atomistic modeling to show that Ag/Ag(100) [regarded as the prototype for smooth growth] actually grows very rough [2]. Furthermore, mound dynamics is seen to be more complex than predicted by standard 3D continuum models.

[1] PRB 68 (03) 121401; SIAM MMS 3 (05); [2] PRB 65 (02) 193407.