''Point Defects in Lead Sulfide: A first-principles study'' N. Mishra and G. Makov Dept. of Materials Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel

The energetic and electronic properties of point defects in lead sulfide were studied using first-principles methods. In particular, intrinsic defects including single-site and double-site defects were considered as well as extrinsic oxygen-containing defects. A novel, stable interstitial site was identified. The convergence of the calculations with supercell size was examined and found to be well-converged for most defects in 250 atom supercells. For intrinsic defects, it was found that, after accounting for the chemical potentials of Pb and S in the environment, the lowest formation energies are associated with lead vacancies in S-rich conditions and sulfur vacancies in Pb-rich conditions and not with Schottky defects, as previously reported. The electronic band structure was affected by the presence of intrinsic defects. The charged states of the point defects were examined and found to be preferred over the neutral states. The formation energies of oxygen defects are highly competitive energetically with those of intrinsic defects, and therefore, oxygen point defects are expected to play a significant role in determining material properties. The authors acknowledge the support of the Pazy Foundation.