Glassy and ballistic dynamics in collision cascades in amorphous TiO2: Combined molecular dynamics and Monte Carlo based studies across energy scales

A Holm and SG Mayr, PHYSICAL REVIEW B, 103, 174201 (2021).

DOI: 10.1103/PhysRevB.103.174201

Kinetics in amorphous TiO2 driven by ion irradiation are discussed in the framework computer simulations. Thermal spike like regions along the path of incident ions are identified and their effects on the glassy system are described. Benefiting from the complementary approaches of purely ballistic TRIM (transport in matter) simulations and molecular dynamics simulations, a distinction between characteristic scales for short-range diffusive relocations (less than or similar to 4.5 angstrom) and long-range ballistic relocations is achieved. It is found that diffusion dynamics within thermally activated cascade zones sets in at the critical temperature T-c, identified as the critical temperature of the mode coupling theory, while the mean relocation limit for thermal diffusion in the glassy system is attributed to an overlap between the energy regime of purely ballistic and thermally activated relocation processes.

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