The stability of thin single-crystal, internal-defect-free Fe films on Mo(110) and W(110) substrates was investigated through calculations of energetics including contributions from the misfit strain, interfacial misfit dislocations, film surface and interface. The misfit dislocation model was developed through the Peierls–Nabarro framework, employing ab initio calculations of the corrugation potential at the film/substrate interface as an input to the model. The surface and interfacial energies for pseudomorphic films were calculated as a function of film thickness from 1 to 10 layers, employing first-principles spin-polarized density-functional theory calculations in the generalized gradient approximation. First-principles calculations were also employed to obtain the Fe surface stress used in the Peierls–Nabarro model to account for the strain dependence of the surface energy. It was found that the competition between the misfit strain, misfit dislocations, film surface and interfacial energies gave rise to a driving force for solid-state de-wetting of a single-crystal, internal-defect-free film, i.e., an instability of a flat film that leads to formation of thicker and thinner regions. The details of the energetics were presented to demonstrate the robustness of the mechanism. The findings indicated that misfit dislocations and their configurations played a significant role in the morphological evolution of metallic thin films.

Stability of Strained Thin Films with Interface Misfit Dislocations: a Multiscale Computational Study. N.Pisutha-Arnond, B.Yang, D.H.Lim, M.Asta, K.Thornton: Thin Solid Films, 2010, 519[2], 809-17