Primary radiation damages in Li2TiO3 and Li4SiO4: a comparison study using molecular dynamics simulation

Molecular dynamics simulations are conducted on β-Li2TiO3 and Li4SiO4 to compare several of their radiation damage-related properties at 0 K. Overall, Li2TiO3 was found to be more tolerant to irradiation damage than Li4SiO4, which is in qualitative agreement with recent experiments. For instance, Li2TiO3 was found to amorphize at 0.55 dpa, while Li4SiO4 amorphized at 0.25 dpa itself. Including the polarization of the O atom while modeling cascades in Li2TiO3 was found to predict a more realistic cascade behavior and defect production. The threshold displacement energies and diffusion coefficients of atoms were calculated for both the materials. Li diffusion was found to be highest when compared to other atoms. For Li4SiO4, the existing interatomic potential predicted an Li diffusion coefficient which is nearly two orders of magnitude higher than what is seen for Li2TiO3. Moreover, this potential predicted Li diffusion at temperatures as low as 583K, making it impossible to compare finite temperature primary damage with Li2TiO3.