The competition between Cu-substrate and Cu-Cu interaction for the four Co-doped TaN surfaces shows that the Cu-substrate interaction is stronger than the Cu-Cu interaction for all adsorption geometries. This indicates that Cu should wet on all four surfaces, since wetting is promoted when the adatom-substrate interaction is stronger than the adatom-adatom interaction. However, the rearrangements of the Co-doped surfaces could impede or complicate the growth process. The most significant differences between the two energy contributions occurs for Co 25 and Co 100 , while the magnitude of the interactions is somewhat more competitive for Co 50-S and Co of the Supporting Information).