Comparative study of Si„001... surface structure and interatomic potentials in finite-temperature simulations

We have performed a comparative study of three widely used classical many-body potentials for silicon ~Stillinger-Weber, Tersoff-2, and Tersoff-3! in connection with finite-temperature simulations of the Si~001! surface. Large-scale constant-pressure Monte Carlo simulations are used to examine the reconstruction of the Si~001! surface, formation of antiphase boundaries, and defect structures such as dimer vacancies. The accuracy of the empirical potentials is compared with first-principles methods and with experimental results when possible. We find that good performance in the static limit ~i.e., at T50 K) does not ensure the suitability of the potential for finite-temperature simulations. The Stillinger-Weber potential is found to give the best overall performance.