Abstract
In this article we review our theoretical work on dislocations in GaN. The methods applied are two distinct approximations to density functional theory: Density functional based tight-binding total energy calculations allow the prediction of low energy core structures and energies of extended defects embedded in larger regions of perfect material. However, whenever less approximate electronic structure calculations are required they are obtained in a localised basis pseudopotential approach. © 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.