We investigate the dewetting dynamics of ultrathin solid metal films. In these films, quantum confinement of electrons is known to produce a complex wetting potential, leading to “magic thicknesses” which are strongly favored energetically. We introduce a kinetic Monte Carlo model which accounts for a magic thickness. When the driving forces are small enough, the dewetting proceeds from the edges of the films and we find two regimes: (i) Regime I: for stronger driving forces, no dewetting rim is formed along the edge of the film, and magic-height fingers perpendicular to the film edge invade the film. (ii) Regime II: for smaller driving forces, magic-height fingers form parallel to the edge of the film. In this regime, a magic-height dewetting rim forms, and subsequently breaks up due to the emergence of two instabilities: rim closure failing, and layer-by-layer nucleation of holes in the film behind the rim. In both regimes, the dewetting velocity and the typical wavelength observed in the simulations are found to be in good agreement with a maximum velocity principle based on a simple model accounting for diffusion limited dynamics. Finally, the labyrinthine morphology resulting from the dewetting process and its typical length scales are found to be consistent with experimental observations. For stronger driving forces, we observe homogeneous nucleation. Depending on the relative values of the magic height and the film height, the dewetting process starts with the formation of holes or with the formation of magic-height islands.

• Received 3 June 2014
• Revised 18 September 2014

DOI:https://doi.org/10.1103/PhysRevB.90.195408