Authors: K. Trachenko, M.T. Dove and E.K.H. Salje
Affilation: University of Cambridge, United Kingdom
Pages: 145 - 176
Keywords: zircon, radiation damage, molecular dynamics
We report the results of simulation of radiation damage in zircon structure using molecular dynamics technique. We detect, quantify and visualise the phases of damage production process, including ballistic and thermal spike phase. The simulation at higher temperature shows the substantial decrease of the damage throughout the damage production. We simulate the overlap of the displacement cascades and find that the damaged structure is less able to resist the damage, in that more damage is produced in the structure that is already damaged, and relaxation time increases. The calculated density of the damaged region shows the increase in its core. We relate this densification to the appearance of connected into chains SiOn polyhedra, n=4,5,6, in the damaged structure. We find that the number of connected polyhedra increases with the increase of damage, consistent with recent NMR results. "Polymers" of connected SiOn are found to be essentially stable on annealing during the timescales available in computer simulations. Their alignment may possess the "memory" of alignment of SiO4 tetrahedra in crystalline zircon.