Atomistic Simulation of the Structural, Thermodynamic, and Elastic Properties of Li2TiO3

Lithium-based ceramics, such as lithium metatitanate, have been proposed for adoption in the breeder blanket region of a fusion reactor. In this article, we report a combination of empirical and density functional theory (DFT) simulations employing "on-the-fly" pseudopotentials for Li2TiO3. The smoothing parameters of the plane-wave pseudopotentials were optimized to ensure an appropriate level of precision for determination of structural, thermodynamic, and elastic properties. As the elastic properties of lithium metatitanate are not well-known, the efficacy of the DFT simulations employing the new pseudopotentials was explored using Li2O and TiO2 where experimental data are available. These pseudopotentials are then used to investigate the three intermediate temperature phases of Li2TiO3 (i.e., C2/c, C2/m, and P3112). Finally, we examine the elastic properties of Li2TiO3 using both DFT and an empirical potential model and find it to be, irrespective of space group, more resistant to deformation than other promising ceramic breeder materials.