The role of screening in the density functional applied on transition metal defects in semiconductors

Abstract

We study selected transition metal related point defects in silicon and silicon carbide semiconductors by a range separated hybrid density functional (HSE06). We find that HSE06 does not fulfill the generalized Koopmans' Theorem for every defect which is due to the self-interaction error in the functional in such cases. Restoring the so-called generalized Koopmans' Condition with a simple correction in the functional can eliminate this error, and brings the calculated charge transition levels remarkably close to the experimental data as well as to the calculated quasi-particle levels from many-body perturbation theory.