We use metastable NaCl-structure Ti${}_{0.5}$Al${}_{0.5}$N alloys to probe effects of configurational disorder on adatom surface diffusion dynamics which control phase stability and nanostructural evolution during film growth. First-principles calculations were employed to obtain potential energy maps of Ti and Al adsorption on an ordered TiN(001) reference surface and a disordered Ti${}_{0.5}$Al${}_{0.5}$N(001) solid-solution surface. The energetics of adatom migration on these surfaces are determined and compared in order to isolate effects of configurational disorder. The results show that alloy surface disorder dramatically reduces Ti adatom mobilities. Al adatoms, in distinct contrast, experience only small disorder-induced differences in migration dynamics.

• Received 23 February 2012

DOI:https://doi.org/10.1103/PhysRevB.85.245422