Theory of Condensed Matter, Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE, U.K.
In this paper we briefly survey the current state of ab initio calculations in terms of the accuracy and range of applicability of these methods for studying complex processes in real materials. We highlight some of the successes and limitations of these techniques and discuss the extent to which linear-scaling methods are able to extend the scope and scale of ab initio calculations. We argue that a combination of linear-scaling methods and hybrid modelling schemes is required to overcome many of the difficulties currently faced by conventional schemes, and present our own contributions towards the development of a robust and reliable linear-scaling method.