Atomic-scale defects play a critical role in determining the functional properties and performance of many solid-state materials, with important implications for semiconductor doping, catalytic active sites, charge-carrier recombination and efficiency in solar photovoltaics, and ionic and electronic conductivity in battery materials. However, the dilute concentrations of point defects often make their experimental characterization extremely challenging. First-principles calculations provide a powerful complementary approach for investigating the structure, energetics, and electronic properties of defects at the atomic scale.

This training session will provide a systematic demonstration of density functional theory (DFT)-based workflows for investigating point defects in solids using MedeA. In particular, the session will cover: (1) exploration of defect configurational landscapes, including vacancies, interstitials, and antisites in multiple charge states using the ShakeNBreakapproach; (2) DFT calculations of defect-containing supercells using MedeA VASP and the doped package integrated within MedeA; and (3) post-processing workflows for calculating and analyzing defect formation-energy diagrams, charge-transition levels, and defect and carrier concentrations. Cadmium telluride (CdTe), a technologically relevant solar photovoltaic material, will be used as a representative material system.