Manifestations of strain-relaxation in the structure of nano-sized Co-2 × 2 islands grown on Ag/Ge(111)-√3 × √3 surface

► We examine strain-relaxation of Co-2 × 2 islands grown on Ag/Ge(111)-√3 × √3 surface. ► The Co-2 × 2 islands are more compact as compared to the substrate. ► No relation between the relaxation and the island height. ► Atomic compactness and atomic order as manifestations of strain-relaxation.