The Mott–Littleton method: an introductory survey

Abstract

This paper aims to provide a broad introduction to the material presented to the conference by surveying the principles of atomistic defect calculations as introduced in the original paper of Mott and Littleton (Trans. Faraday Soc., 1938, 34, 485) and as developed subsequently. Developments in computational techniques, as by the HADES program, have allowed essentially exact representations of particular models to be obtained within the framework of the Mott–Littleton principles. Characteristic defect energies obtained by these methods over the years have provided guidance on the interpretation of observed properties of ionic solids. More recently, the enlargement of the Mott–Littleton principles within the framework of the quasi-harmonic approximation and by reference to the thermodynamics of characteristic defect quantities has allowed the accurate calculation of defect enthalpies, entropies and free volumes as functions of temperature and, if need be, of pressure. It seems likely that such calculations will continue to be valuable in the future as yet more refined and varied models of ionic solids are considered.