Defects and impurities were often decisive in determining the physical properties of most materials. The process of defect identification and characterization was typically difficult and indirect, usually requiring an ingenious combination of different experimental techniques. First-principles calculations had emerged as a powerful microscopic tool that complements experiments or sometimes even served as the sole source of atomistic information due to experimental limitations. Still, first-principles calculations based upon density functional theory in the local density or generalized gradient approximations suffer from serious limitations when describing defects in solids. Recent advances in electronic structure methods, rapid increases in computing power, and the development of efficient algorithms indicated a promising future for computational defect physics. Recent advances in the theory of defects in solids from the perspective of first-principles calculations were reviewed. Attention was focussed on methods which improved the description of band-gaps, leading to results that could be directly compared to experiments at a quantitative level. The use of LDA+U in wide-band-gap materials, screened hybrid functionals, the quasiparticle GW method, and the use of modified pseudopotentials were considered. Advantages and limitations of these methods were illustrated, with examples.

Advances in Electronic Structure Methods for Defects and Impurities in Solids. C.G.Van de Walle, A.Janotti: Physica Status Solidi B, 2011, 248[1], 19–27