Molecular dynamics simulations of the laser ablation of silicon with the thermal spike model

The purpose of this work is to model laser ablation of silicon on an atomistic scale in combination with a mesoscale model for the description of the electron-phonon interaction and an electron-temperature dependent interaction potential. The well-known continuum two-temperature model (TTM) for solids with highly excited electrons is extended from metals to silicon by explicitly taking charge carrier transport effects into account (nTTM). This is accomplished by the drift-diffusion limit of the Boltzmann-transport equation leading to the so called thermal-spike model (TSM). The model is further enhanced by extending the static modified Tersoff potential to a dynamical carrier excitation dependent interaction potential. We compare the TSM and nTTM with regard to physical correctness, numerical stability and applicability in the context of large-scale massive parallel high performance computing.

Automated summary

The aim of this work is to model laser ablation of silicon on an atomistic scale using a mesoscale model for electron-phonon interaction and electron-temperature dependent potential. The widely used two-temperature model for highly excited electrons in metals has been extended to silicon by considering charge carrier transport effects (nTTM). The model is further improved by introducing a dynamic interaction potential dependent on carrier excitation. Comparisons were made between different models in terms of physical accuracy, numerical stability, and applicability in large-scale parallel computing.