Effects of nonlocal interactions in describing V centers of MgO

Abstract

The electronic structure and optical absorption spectrum of V 0 and center in MgO are investigated based on the density functional theory. The V-type centers are well described when the local symmetry around Mg vacancy is destroyed by using the nonlocal hybrid functionals. It is demonstrated that the holes are trapped on one (or two) O atoms around Mg vacancy for (or V 0) center. The defect states are separated from the valence bands due to the nonlocal exchange interactions involved in the hybrid functionals, which is the key to describing the optical properties correctly. At ambient condition, the absorption peaks ∼2.5 eV and ∼2.6 eV are assigned to V 0 and center, respectively, and they exhibit blue shift with increasing pressure.