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

Employing a generalized lattice gas thee; and the Brownian dynamics simulat ion, we show that the competing displacive interaction in an adsorbate may cause a continuous distortive transition in the underlying substrate. The t hreshold for the transition is determined by the competition of the substra te rigidity and the quasielastic energy induced by the adsorbate. In the pr esence of a strong pinning and repulsive lateral interaction, the resulting structure appears as a compromise between the square lattice of the substr ate and the hexagonal arrangement of the adsorbate. For hexagonal substrate :lattices the simulation demonstrates that various adsorbate structures (fr om honeycomb lattices to quasi crystalline pentagonal configurations) may b e observed, depending on the effective radii of interaction. Due to the lon g-ranged coupling the substrate may acquire a substructure induced by the a dsorbate. This paper represents a generalization of the work published in P hys. Rev. Lett. 81, 3904 (1998). [S1063-651X(99)01107-1].