Formation of linear structures of Sr and Gd films on the Mo(1 1 2) and W(1 1 2) surfaces

Abstract

At low coverages, alkaline earth and rare earth layers adsorbed on furrowed transition metal surfaces––such as W(1 1 2) and Mo(1 1 2)––tend to form commensurate linear structures built of monoatomic chains directed across the furrows. Presented Monte Carlo simulations provide insight into parameters of the long-range indirect interaction that, in competition with a dipole–dipole interaction, leads to formation of the linear structures. The most impressive result of the simulations is the revealed repulsive effective interaction between adjacent atoms in linear Sr chains on W(1 1 2) surface. In this case, formation of the linear chains is accomplished due to pronounced minima in the potential of indirect interaction along the surface furrows. This result predicts that a single Sr chain cannot exist on the W(1 1 2) surface.