Dynamics of Two-Dimensional Ordering: Oxygen Chemisorbed on the W(112) Surface

Low-energy electron diffraction has been used to study the dynamics of formation of oxygen $p(2\mathrm{}\times 1)$ superlattice structure on a W(112) surface at a half-monolayer coverage. The ground state of the $p(2\mathrm{}\times 1)$ structure is twofold degenerate and the nonconserved long-range order associated with this structure was found to grow linearly with time in the earlier stages. This behavior is interpreted with use of the domain-growth theory proposed by Lifshitz and by Allen and Cahn. The temperature dependence of the growth rate obeyed an Arrhenius law for $\frac{T}{T_c}<~0.4$.