Sensitivity of the threshold displacement energy to temperature and time

Abstract

The impact of temperature and time scale on the threshold displacement energy (${E}_{d}$) has been investigated using molecular dynamics simulation. Employing a systematic approach to simulating low energy displacement cascades, defect formation probability has been quantified and precise values of ${E}_{d}$ have been calculated at temperatures of 50, 300, 750, and 1200 K. In application to rutile TiO${}_{2}$, the thermal activation of Frenkel pairs at elevated temperatures is found to significantly reduce defect formation probability and cause an increase in the oxygen value of ${E}_{d}$. Relating the high-temperature, picosecond simulations to experimental measurement conditions, we find that thermally activated processes are responsible for discrepancies in values of ${E}_{d}$ reported by various techniques. This work establishes that ${E}_{d}$ is not an intrinsic material property but depends on the conditions in which it is measured and the context in which it is to be used.