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Stress and displacement fields of a two-dimensional solid under plane strain are solved subject to surface reconstruction boundary conditions. The alternating lateral Dirac-δ forces at steps owing to the reconstruction obtained by Alerhand et al (1988 Phys. Rev. Lett. 61 1973–6) are recovered from the gradient of the stress field solution. Sinusoidal vertical and lateral displacements on a terrace are obtained, in addition to the vertical force distribution, in the direction normal to the surface. Reconstructed periodic terraces reduce their elastic energy by increasing their average width, but the elastic energy density reaches a finite limit with an increased terrace width. A like-oriented step–step interaction with the force dipole from the surface reconstruction, using the Marchenko–Parshin model, is considered and found to be repulsive. Reconstructed terraces of a vicinal surface are thermodynamically stable when the surface has a large dangling bond energy and a large miscut angle. Small miscut angle or small surface tension tends to destabilize the surface, although our result suggests that a multilayer configuration will metastabilize the terraces owing to the interface elastic mismatch.

A concise formula expressing the entropy of adatoms as a divergence of their flow due to diffusion and deposition flux is presented. Adatom-elastic strain interaction is provided by a canonical coupling between the diffusion flow and the deformation gradient of the strained layer. It is found that the zero of the free energy of an adatom-strained layer continuum system should be that of a coherent unstrained layer, thus necessarily neglecting the cohesive energy contribution, while for the adatom-unstrained continuum layer the zero corresponds to an equilibrium between the adatoms and free atoms, which involves the cohesive energy.

Island size distributions of three-dimensional Si1−xGex/Si(001) islands of varying Ge fractions (x=0.4–0.7) and thicknesses grown by ultrahigh vacuum chemical vapor deposition are studied. Size distributions for percolating islands obey the dynamic scaling hypothesis due to a random percolation process, only in the small island limit. Island morphologies strongly suggest the presence of Smoluchowski ripening, in which islands collide and ripen. Random percolation and Smoluchowski ripening are thus combined to analyze the size distributions. To understand the critical behavior of the islands, as exhibited by their size distributions, a mean-field theory for coherently strained island formation is formulated, by incorporating surface energy and strain relaxation. The resulting phase diagram shows that island formation in Si1−xGex/Si(001) occurs near the critical region. Order parameter fluctuations can be estimated by calculating the curvature energy for such a system, showing that the strain fluctuations a...

We report here on the fabrication of porous anodic alumina (PAA) films from commercially available impure aluminum foil. While the expensive ultrapure PAA films are restricted to potential applications in nanoelectrophotonics, the impure PAA films are more suitable for large-scale applications, such as in catalysis and filtration. The anodization current behavior and chemical composition of the resulting PAA films from impure and ultrapure foils were found to be similar for the same set of anodizing conditions. However, the PAA films from impure aluminum foil contained pore arrays of much smaller size and less consistently sized pores than those of PAA from ultrapure foils. We find that these qualities are improved by either annealing or electropolishing the aluminum foil prior to anodization, although not to the degree of PAA produced from ultrapure foils. Greater improvement is found for annealed foils compared to electropolished foils.