Tight-binding molecular-dynamics study of defects in silicon

A tight-binding molecular-dynamics scheme is shown to have the efficiency and accuracy to study complex Si systems. We first establish the reliability of the scheme by showing that simulation results of liquid Si are nearly identical to ab initio (Car-Parrinello) results. The ability of the method to study complex systems is demonstrated by calculating defect formation energies and atomic configurations around vacancies and self-interstitials, with simulation unit cells of up to 512 atoms. The calculated formation energies compare well with first-principles results.