Self-diffusion of one-dimensional clusters on fcc (110)(2×1) surfaces of Pt, Ag, Cu, and Ni

We theoretically investigate self-diffusion processes of one-dimensional adatom clusters of three to five atoms on reconstructed (110)(2×1) surfaces of Pt, Ag, Cu, and Ni. We consider single clusters on the surfaces as well as collective processes when additional atoms are present in neighboring rows of the (110)(2×1) surface. For several diffusion mechanisms and configurations we calculate activation barriers and preexponential factors from local vibrational density of states. The trends for the activation barriers are the same for the four metals, indicating that the geometry of the rough, anisotropic surface plays a key role. Prefactors are found to be in the usual range of 10^-3 cm²/s. Additional atoms in neighboring rows lead to a small lowering of activation barriers, while prefactors do not change significantly.