First-principles calculations of native defects in beryllium oxide

Beryllium is the main plasma-facing material used in the International Thermonuclear Experimental Reactor (ITER) and is likely accompanied by its oxide, BeO. BeO is a ceramic and is used as a transparent coating on optical components. BeO is stable in the wurtzite phase and boasts several useful properties, including high thermal conductivity and an ultra-wide band gap exceeding 10 eV. The large band gap makes BeO promising as a host for quantum defects. The technological relevance for reactors and coatings and potential for quantum information applications highlight the importance of a thorough understanding of the defect chemistry of BeO. We study these defects using first-principles density functional theory calculations with a hybrid functional. We examine the energetics and electronic structure, as well as the atomic geometries and spin properties of the native defects of BeO. We compare the properties of the native defects of BeO with those in other group-II oxides, which generally prefer the rocksalt phase, and with diamond, a tetrahedrally coordinated material known to host quantum defects.