Simulations of GaN using an environment-dependent empirical tight-binding model

We have developed an empirical, total-energy tight-binding model for gallium nitride which we have used in molecular-dynamics simulations of the bulk material as well as several native point defects. The Ga-N and N-N interactions are treated using the standard two-center approximation whereas the Ga-Ga interactions contain three-body effects that make these interactions sensitive to the local environment of the Ga atoms, thus making the model more transferrable than a strictly two-center model. The parameters of this model provide a good fit to experimental data and ab initio calculations.