Abstract
The formation of nanometer-scale c(2×2) domains and their dynamical fluctuation have been observed on O/Cu(100) surface around 0.3 ML oxygen coverage. We study the origin of both the formation of nanometer-scale domains at 450 K and their fluctuation at room temperature, using the dynamical Monte Carlo simulation of the lattice gas model of adsorbed oxygen atoms. We show that the competition between the attractive short-range interaction and the repulsive long-range interaction between adsorbed oxygen atoms brings about frustration between antiphase c(2×2) domains. This frustration causes the suppression of domain size and the dynamical fluctuation of the domain boundaries. The simulated c(2×2) double domain structure and the fluctuation behavior of the domain boundaries agree with the properties observed by scanning tunneling microscopy and reproduce well the four-spot pattern around the ½-order positions observed by low energy electron diffraction.