Native defects and impurities in InN:: First-principles studies using the local-density approximation and self-interaction and relaxation-corrected pseudopotentials

We perform first-principles density-functional calculations to investigate the electronic and atomic structure and formation energies of native defects and selected impurities (O, Si, and Mg) in InN. For p-type material, the nitrogen vacancy has the lowest formation energy. In n-type material all defect formation energies are high. We discuss the effect of the band-gap underestimate in density functional theory (DFT), and compare the defect electronic structure obtained using DFT (in the local-density approximation LDA) with a recently developed self-interaction and relaxation-corrected (SIRC) pseudopotential treatment. The SIRC calculations affect the positions of some of the defect states in the band gap, but the general conclusions obtained from the standard DFT-LDA calculations remain valid.