A new interatomic potential for the ferroelectric and paraelectric phases of LiNbO3

This paper reports a new interatomic potential for lithium niobate, which has been fitted to the structure and properties of the stoichiometric ferroelectric phase of the material. The potential is based on a fully ionic description of the material, with the shell model being used for the oxygen ions and a three-body potential representing the interactions of the niobium ions with the neighbouring oxygen ions. The potential set has been tested on the paraclectric phase, whose structure it reproduced to within a few per cent. The calculation of lattice properties including elastic constants and dielectric constants, as well as powder x-ray diffraction patterns of both phases, are reported.