Ostwald ripening of close-packed and honeycomb islands during coadsorption

摘要

To mimic the self-assembly of hexagonally shaped molecules such as cyanuric acid and melamine, we present Monte Carlo simulations of the growth of close-packed and honeycomb islands during adsorption and coadsorption of A and B particles on a triangular lattice. Each particle occupies a single site and is characterized by its orientation on the lattice. The orientation is changed by rotation by 60°, so that the rotation by 120° does not change the Hamiltonian. The model predicts slow or nearly negligible island growth at t ≤ 10~3 Monte Carlo steps (MCSs) and then faster growth. On the late stage (10~5 ≤ t ≤ 10~6 MCSs), the growth exponent is found to be 0.28-0.30 in the case of adsorption of particles of one type and 0.24-0.29 in the case of coadsorption. These values are somewhat or appreciably lower than the Lifshitz-Slyozov exponent x=1/3.