First principles calculations of intrinsic breakdown in covalently bonded crystals

A first principles quantum-mechanical method has been developed for estimating intrinsic breakdown strength of insulating materials. The calculations are based on an average electron model which assumes breakdown occurs when the average energy gain from the electric field and phonon absorption exceeds average energy loss to phonons. Our approach is based on density functional perturbation theory (DFPT) and on the direct integration of electronic scattering probabilities over all possible final states, with no adjustable parameters. Computed intrinsic breakdown field is provided for several covalently bonded materials and compared with experimental data from the literature with good agreement. The numerical model provides physical insight into the material properties which affect breakdown.