Cluster adsorption and migration energetics on hcp Ti (0001) surfaces via atomistic simulations

Highlights: • The Ti adatom diffusion energy barrier on the Ti(0001) surface is ≤0.09 eV. • The adsorption energy of a Ti adatom on Ti (0001) is −2262 eV for hcp and is −2245 eV for fcc sites. • The dissociation energy oscillates with respect to cluster size. -- Abstract: We use the modified embedded atom method in the framework of molecular statics to investigate the energetics of Ti adatom and Ti_n (2 ≤ n ≤ 7) cluster adsorption and migration on hcp Ti(0001) surfaces. We have examined several parameters such as the lattice constant, elastic constants, the cohesive energy and the surface energy and we have found that the modified embedded atom method gives results in good agreement with experimental and other theoretical investigations. The Ti (0001) surface multilayer relaxation results show that the distance between the first and second layer is contracted by −5.0%, which is the usual phenomenon for low index metallic surfaces. In addition, the diffusion parameters such as adsorption energies and energy barriers for single-atom and bi-dimensional clusters were derived. These calculations show that the adsorption energy and the potential barrier increase when the cluster size increases indicating their mobility decreases. Which indicates that the mobility of the cluster decreases as the cluster grows.