MD calculation studies of residence site and diffusion path of Li ions in perovskite-type (LaLi)TiO3

A computer simulation is performed by a molecular dynamics method to study the structural and dynamical properties in superionic conductor La4/3-xLi3x square 2/3-2xTi2O6 (square = vacancy), which is the perovskite-type Li ion conductor. At low Li concentrations, Li ions conduct with a two-dimensional motion, while Li ions diffuse with a three-dimensional motion at high Li ion concentrations. The partial distribution function for Li-Ti and the diffusion paths of Li ions suggest that Li ions stay for a long time at off-site positions which are 2.7 angstrom away from a body-centered Ti ion. The Li ion concentration dependence of or is in approximate agreement with experiments.