Cooperative Phase Transformation in Self-Assembled Metal-on-Oxide Arrays

The thermal behavior of a composite system formed by gold nanoclusters self-organized on a TiOx/Pt(111) ultrathin film is investigated via first-principles simulations. A cooperative phase transformation from a rectangular to an hexagonal phase occurs at high temperature, by which Au clusters do not coalesce, but rearrange their shape and positions together with the more mobile regions of the oxide. A model describing the atomistic processes behind this transformation is proposed that is in full agreement with available experimental data.