Atomistic simulations of radiation induced defect formation in the Er2O3 sesquioxide

Molecular dynamics simulations of collision cascades were performed in Er2O3 to determine the displacement energy thresholds, the main types of defects that form and the structure of the collision cascades. The displacement energy thresholds have a small variation, depending on direction, for Er but a much larger variation for O. Due to the large mass difference, when an Er atom is the primary knock-on, a dense cascade forms around the initial radiation event whereas the O cascades are more diffuse with subcascade branching. A wide variety of point defects were found to occur all of which had relatively high energy barriers for diffusion, with the lowest barrier being the oxygen vacancy which has to overcome barriers of 0.8 eV and 1 eV for net diffusion.