Theory and computer simulation of perfect and defective solids

Crystalline solids have become a subject of growing interest for both experimentalists and theorists. In particular their defect properties are of fundamental importance in modern and future technical applications. The efficiency of fuel cells and batteries strongly depends on the mobility of ions in the lattice which is affected by various kinds of point defects and the local crystal structure. Fundamental understanding of processes involved in ion migration at atomic scale can be achieved by combined spectroscopical and theoretical investigation. During the last decades theoretical methods have become an indispensable tool for studying solid state materials. A broad variety of methods and models are available, all of them with peculiar benefits. In this review article an overview of some state-of-the-art methods and model types is given with a focus on their applicability to studies of defects and ion mobility.