Sensitivity of the threshold displacement energy to temperature and time

Abstract

The impact of temperature and time scale on the threshold displacement energy (Ed ) 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 Ed have been calculated at temperatures of 50, 300, 750, and 1200 K. In application to rutile TiO2, 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 Ed . Relating the high-temperature, picosecond simulations to experimental measurement conditions, we find that thermally activated processes are responsible for discrepancies in values of Ed reported by various techniques. This work establishes that Ed 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.