The electronic structure of neutral and charged surface vacancy defects in periclase

Abstract

An understanding of the electronic structure of defects on mineral surfaces is critical to the development of microscopic models of the chemistry which occurs at these surfaces in natural environments, and in catalytic applications. In this work, the formation energies and electronic structure of neutral and charged surface oxygen vacancy defects (F s, F + s and F 2+ s centers) on the (001) cleavage face of periclase (MgO) are computed using a recently developed ab-initio electronic structure method. The position of the defect state in the fundamental energy gap of MgO is found to be in qualitative agreement with a model for optical absorption and emission, and energy-dependent electron energy-loss experiments, and is used to explain the formation energies of these defects.