Isolated single vacancy in diamond—I. Electronic structure

Abstract

Some of the assumptions underlying the molecular approach to the determination of the electronic properties of the vacancy in diamond have been examined. The ordering of the lowest electronic levels of the neutral and single negatively charged states of the vacancy is sensitive to the choice of atomic functions to represent the 2 s and 2 p orbitals on the atoms nearest the defect as well as to the symmetric relaxation of these atoms. However, for limited delocalisation of electronic charge from the vacancy there is no change in the ordering of the lowest levels. The 3 T 1 electronic state is predicted as the ground state of the neutral vacancy if the atoms nearest the defect relax towards its centre as implied by the molecular model; however, for a symmetric relaxation of the nearest neigh-bours away from the centre of the vacancy the 1 E level is more likely to be the lowest level. Present experimental knowledge of the vacancy in diamond does not resolve this uncertainty.