Effect of electronic stopping in molecular dynamics simulations of collision cascades in gallium arsenide

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 different communities, from space radiation effects 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 self-projectiles in different 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 effects of electronic stopping in molecular dynamics simulations of collision cascades in a multielement semiconductor and that the number of defects is considerably affected by electronic stopping effects. The results are also discussed in the wider context of the commonly used nonionizing energy loss model to estimate degradation of materials by cumulative displacements.

Automated summary

Understanding the generation and evolution of defects induced by ion irradiation is vital for estimating the degradation of material properties. This study investigates collision cascades in GaAs and demonstrates the significant impact of electronic stopping on the number of defects. The results also contribute to discussions on estimating material degradation using nonionizing energy loss models.