The importance of polarizability in the modeling of ionic diffusion in ceria

Classical molecular dynamics can be used to investigate ionic diffusion and its limitations in trivalently doped ceria and at the surfaces and interfaces of these materials. Here we compare the performance of two interatomic potentials derived for samarium doped ceria from the same set of ab-initio data, a dipole polarizable ion model (DIPPIM) and a rigid ion model (RIM). The DIPPIM allows for polarization effects resulting from induced dipoles whereas the RIM does not. In this study we aim to elucidate whether or not this system can be modelled successfully using a RIM or if a DIPPIM is necessary due to the large polarization effects caused by the presence of oxide (O²⁻) ions. (paper)