Abstract:
We have studied the reconstruction of Pt(111) theoretically using a two-dimensional Frenkel-Kontorova model for which all parameters have been obtained from ab initio calculations. We find that the unreconstructed surface lies right at the stability boundary, explaining why it is easy to induce the surface to reconstruct into a pattern of fcc and hcp domains. The experimentally observed “rotors” at intersections of domain walls are shown to arise from a slight rotation of the top layer relative to the substrate. The size and shape of domains are very sensitive to the density in the top layer, the angle of rotation, and the chemical potential, with smooth transformations between different patterns that include the honeycomb, wavy triangles, bright stars, and Moiré pattern. This shows that the same physics is operating in the various homoepitaxial and heteroepitaxial systems for which these different patterns have been reported, with the apparent differences arising from very slight changes in parameters
