50+ years of intrinsic breakdown
The basic quantum mechanical theory for intrinsic breakdown was developed by von Hippel and Fröhlich over 70 years ago, but only now can we exploit their ideas accurately through the use of computational quantum mechanics. As shown above, von Hippel's low energy criterion for intrinsic breakdown provides remarkably good agreement with measured data for a range of both ionic and covalently bonded materials. We can correlate intrinsic breakdown with both bandgap and phonon cutoff frequency, although the relationships differ for different groups of materials. The challenge going forward is to move from intrinsic breakdown to engineering breakdown through inclusion of effects caused by morphology, chemical impurities (impurity states in the bandgap), and defects such as nanocavities. We believe that inclusion of these phenomena is possible using Monte Carlo computations with parameters computed using first principles methods, and we are pursuing this approach.