Ge(001) surface reconstruction studied using a first-principles calculation and a Monte Carlo simulation

The problem of the relative energetic stabilities of high-order reconstructions of the Ge(001) surface is revisited with more refined first-principles calculations. Deducing the parameters of the Ising model from this result, we perform Monte Carlo simulations of the phase transition of the asymmetric dimer directions. The Monte dado simulation reproduces fairly well the experimental transition temperature of an x-ray-diffraction experiment. The potential-energy curve of the dimer flip-flop motion in the p(2 x 1) structure is determined. The obtained geometry of the c(4 X 2) structure also agrees fairly well with the results of an x-ray diffraction experiment.