Non-Adiabatic Quantum Molecular Dynamics Investigation of Hot Carrier Dynamics in Dielectric Polymers under High Electric Fields.

Non-Adiabatic Quantum Molecular Dynamics (NAQMD) is a powerful tool typically used to model excited state electron-phonon dynamics under optical excitation. In this work we have ported NAQMD to study excited hot charge carriers involved in dielectric break down of organic polymers under high electric fields. Organic polymers offer many advantages over inorganic dielectrics, but they are severely limited by break down under the application of high electric fields. There also remains no mechanistic method for quantitative prediction of the breakdown field in polymers, unlike inorganic materials. Here we performed a systematic study of different electric fields on hot carrier dynamics and resulting chemical damage in a slab of archetypal polymer, polyethylene. We found a critical transition occurring near the experimentally reported intrinsic breakdown field marked by strong localization of electronic states at the slab surface and emergence of hot carrier C-H vibrational resonance. Such a localization transition may provide a critically-missing prediction method for computationally screening dielectric polymers with high breakdown fields.