book of abstracts - IM2NP

A B S T R A C T S THURSDAY, JULY 1 N A N O S E A 2 0 1 0
based on 2D nucleation theory and diffusion-limited dynamics. When dewetting is heterogeneous, i.e.
dewetting is initiated at pre-existing holes, or at the film edge,two regimes are obtained.
A regime with a facetted multi-layer rim, where the front position scales as $t^{1/2}$, and a layer-by-layer
dewetting regime where a monolayer islandnucleated far from the dewetting front invades the whole film. In
contrast, during homogeneous dewetting, where holes arise from fluctuations in a perfect and clean system,
multi-layer rims always form.
3 – Conclusion
Ultra-thin crytalline solid films are found to dewet with a facetted rim. In the case of heterogeneous
dewetting initiated from a linear trench or from periodically arranged holes, the dewetted area expands
either with a facetted multi-layer rim or in a layer by layer fashion. In the case of homogeneous dewetting,
holes are accompanied with multi-layer rims and the uncoverage increases as a power law of time. Results of
kinetic Monte Carlo simulations are elucidated within the frame of nucleation theory and surface diffusion
limited dynamics.
[1] Dewetting of a Solid Monolayer O. Pierre-Louis, Anna Chame, and Yukio Saito, Phys. Rev. Lett. 99, 136101 (2007).
[2] Dewetting of Ultrathin Solid Films O. Pierre-Louis, A. Chame, and Y. Saito, Phys. Rev. Lett. 103, 195501 (2009).
[3] Atomic step motion during the dewetting of ultra-thin filmsO. Pierre-Louis, A. Chame, M. Dufay, preprint (2010).
12H30-13H00
Coarse-Grained Theory of Growth on Patterned Substrates.
C. A. Haselwandter and D. D. Vvedensky (CAH: Department of Applied Physics, Califonia Institute
of Technology, Pasadena, CA 91125, USA, DDV: The Blackett Laboratory, Imperial College London, London SW7
2AZ, UK). cah77@caltech.edu, d.vvedensky@imperial.ac.uk.
1 – Introduction
We present a stochastic continuum theory of the formation of surface nanostructures in several experimental
settings. The first step of our methodology is the systematic transformation of a lattice model for a particular
system into a stochastic continuum equation of motion. With these regularized equations as initial
conditions, renormalization group (RG) equations are formulated for the changes in the model coefficients
under coarse graining. The solutions of the RG equations yield trajectories that describe the original model
over a hierarchy of scales, ranging from transient regimes, which are of primary experimental interest, prior
to the crossover to the asymptotically stable fixed point. Thus, our method yields continuum equations that
describe atomistic growth models over expanding length and time scales, but retain a direct connection to the
underlying atomistic transition rules.
2 – Abstract
Our interest here is in the transient regime for several experimental scenarios, where the growth conditions
play a central role in determining the form of the governing equation. We first briefly consider the regimes
defined by the relative magnitudes of the diffusion and deposition noises. If diffusion noise dominates, then
the early stages of growth are described by the Mullins-Herring (MH) equation with a conserved noise. This
is the classical regime of molecular-beam epitaxy (MBE). If the diffusion and deposition noises are of
comparable magnitude, the transient equation is the MH equation, but with nonconserved noise. This
behavior has been observed in a recent report of Al on silicone oil surfaces. Finally, the regime where
99