Energetic, vibrational, and electronic properties of silicon using a nonorthogonal tight-binding model

We present calculations of energetic, electronic, and vibrational properties of silicon using a nonorthogonal tight-binding ~TB! model derived to fit accurately first-principles calculations. Although it was fit only to a few high-symmetry bulk structures, the model can be successfully used to compute the energies and structures of a wide range of configurations. These include phonon frequencies at high-symmetry points, bulk point defects such as vacancies and interstitials, and surface reconstructions. The TB parametrization reproduces experimen- tal measurements and ab initio calculations well, indicating that it describes faithfully the underlying physics of bonding in silicon. We apply this model to the study of finite temperature vibrational properties of crystal- line silicon and the electronic structure of amorphous systems that are too large to be practically simulated with ab initio methods.