Co 25 and Co 50-F are both thermally stable and the geometry of the initial rhombus structure of Cu 4 before and after the aiMD run are shown in Figure . The results from the aiMD simulations support our initial hypothesis that these surfaces should promote wetting of Cu. On Co 25 , one of the Cu atoms separates from the cluster, as shown in Figure . This is accompanied by some surface distortions, which cause a Ta atom be pushed partially out of the surface layer. The effect such distortions would have on surface roughness and stability require a much larger model and are outside the scope of this study. The other three atoms remain at their original positions from the relaxed starting geometry, however a single atom migrating away from the cluster supports our idea that there is a preference for fewer Cu-Cu interactions on this surface. Similarly, on Co 50-F , the rhombus rearranges into a line configuration along a row of Co dopants, as shown in Figure . This is likely caused by the strong interactions between Co and Cu, allowing the Co dopant to act as a nucleation site in the surface, similarly to Ru dopants as On W 25 the less favourable rhombus with three atoms in a line rearranges into a square after 5 ps at 500 K. Each atom is adsorbed at a site A, thus increasing the number of Cu-Cu interactions compared to the 0 K geometry (see Figure ). The Cu 4 structure on W 50-S remains unchanged after 5 ps at 500 K (see Figure ). On W 50-F , it appears that the atoms migrate across the surface toward the nearest A sites and begin forming into the same square structure observed for W 25 (see Figure ). On W 100 , the rhombus rearranges into a tetrahedron, even though this geometry was not as favourable during the standard geometry relaxations (see Figure ). The tetrahedron was most favourable on W 25 , however the fact that the rhombus structure did not rearrange into a 3D structure at 500 K, as well as the favourable Cu-substrate interaction, indicates that 25% W could be enough to prevent Cu island formation, while 100% W is potentially too high of a doping concentration, in that it will be similar to TaN.