Parametric study of the Two-Temperature Model for Molecular Dynamics simulations of collisions cascades in Si and Ge

The sensitivity of collision cascades simulations to the Two-Temperature Model main parameters is investigated by performing an extensive statistical study both in Si and Ge materials. The purpose is to identify the parameters of the Two-Temperature Model whose impact is the most significant on the cascades properties and to discuss the physical role of each parameter. We demonstrate that the electronic stopping power and electron-phonon coupling have a drastic impact both in Si and Ge but that these two parameters act differently on those two materials due to their distinct thermal properties. We show that the formation of thermal spikes and therefore of amorphous pockets is sensitive to the electronic specific heat. The effects are again very distinct in Si and in Ge. The influence of both the threshold velocity for the stopping power and the electron-phonon coupling activation time are found to be negligible at the considered energies.