Lateral interactions and zigzag chains of Ho on the Mo(110) surface

The structure of Ho adsorbed layers on the Mo(110) surface has been studied by low energy electron diffraction (LEED) and scanning tunneling microscope (STM). It has been found that at submonolayer coverages Ho atoms, similarly to studied earlier Gd and Nd, form a rich amount of dilute (n × 2) commensurate structures built from zigzag chains oriented along the [11̅0] direction. The formation of zigzag chain structures is initiated by the indirect lateral interaction between adsorbed Ho atoms, which, as is illustrated by Monte Carlo simulations, can be well approximated by a screened Coulomb potential superimposed with Friedel oscillations.

► We found that Ho forms the sequence of linear structures on Mo(110). ► These structures are in form of zigzag chains oriented along the [11̅0] direction. ► Ho on Mo(110) forms very dilute (22 × 2), (18 × 2) and (14 × 2) structures. ► The substrate affects the sequence of forming structures as the coverage increases. ► The formation of zigzag chains is accomplished due to indirect lateral interactions between Ho atoms.