Predictions of bandgap and subbands of γ−Al 2 O 3 in presence of intrinsic point defects by DFT+TB-mBJ

Abstract

The electronic structure of γ-Al 2 O 3 in the presence of the Al and O defects is investigated within the density functional theory using the PBE-GGA and TB-mBJ schemes. The formation of the Al vacancy produces acceptor-like sublevels above the valence band maximum, consistent with the previous G 0 W 0 calculations. Furthermore, the formation of the oxygen vacancy generates donor-like sublevels below the conduction band minimum, which is consistent with experiment. The donor sublevels are predicted more accurately by TB-mBJ than PBE-GGA, as electron charge density is calculated to be larger at the O vacancy site by TB-mBJ within its optimized c-factor. © 2019 Elsevier B.V.