On the effect of electronic stopping in molecular dynamics simulations of collision cascades in Gallium Arsenide

Abstract

Understanding the generation and evolution of defects induced in matter by ion irradiation is of fundamental importance to estimate the degradation of functional properties of materials. Computational approaches used in dierent communities, from space radiation eects to nuclear energy experiments, are based on a number of approximations that, among others, traditionally neglect the coupling between electronic and ionic degrees of freedom in the description of displacements. In this work, we study collision cascades in GaAs, including the electronic stopping power for selfprojectiles in dierent directions obtained via real time Time Dependent Density Functional Theory in Molecular Dynamics simulations of collision cascades, using the recent electron-phonon model and the previously developed two-temperature model. We show that the former can be well applied to describe the eects of electronic stopping in molecular dynamics simulations of collision cascades in a multielement semiconductor and that the number of defects is considerably aected by electronic stopping eects. The results are also discussed in the wider context of the commonly used non-ionizing energy loss model to estimate degradation of materials by cumulative displacements.