Structural rearrangement of solid surfaces due to competing adsorbate-substrate interactions

Employing a generalized lattice gas theory and the Brownian dynamics simulation, we show that the competing displacive interaction in an adsorbate may cause a continuous distortive transition in the underlying substrate. The threshold for the transition is determined by the competition of the substrate rigidity and the quasielastic energy induced by the adsorbate. In the presence of a strong pinning and repulsive lateral interaction, the resulting structure appears as a compromise between the square lattice of the substrate and the hexagonal arrangement of the adsorbate. For hexagonal substrate lattices the simulation demonstrates that various adsorbate structures (from honeycomb lattices to quasicrystalline pentagonal configurations) may be observed, depending on the effective radii of interaction. Due to the long-ranged coupling the substrate may acquire a substructure induced by the adsorbate. This paper represents a generalization of the work published in Phys. Rev. Lett. 81, 3904 (1998).