  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.
