Mechanisms of Radiation-Induced Viscous Flow: Role of Point Defects

Mechanisms of radiation-induced flow in amorphous solids have been investigated using molecular dynamics computer simulations. It is shown for a model glass system, CuTi, that the radiation-induced flow is independent of recoil energy between 100eV and 10keV when compared on the basis of defect production and that there is a threshold energy for flow of ≈10 eV. Injection of interstitial- and vacancylike defects induces the same amount of flow as the recoil events, indicating that point-defect-like entities mediate the flow process, even at 10K. Comparisons of these results with experiments and thermal spike models are made.