No abstract

No abstract

The authors report results of atomistic simulation studies of the formation of intrinsic defect structures in YIG. Using calculated defect formation energies they obtain energies for defect reactions, from which they determine the most favourable defect processes in yttrium iron garnet. Finally, they comment on some electronic properties of YIG crystals.

In this paper we present embedded-cluster calculations on singly charged and neutral oxygen vacancies (or F centres) in the oxide perovskite BaTiO3. The simulations include Hartree-Fock theory with MP2 corrections and density-functional-theory calculations for a central quantum defect cluster and a pair-potential description of the embedding lattice. All important defect-induced lattice distortions are taken into account in this way. We discuss the possible electronic states of charged F centres and the effects of nearby acceptor-type defects. It is shown that isolated oxygen vacancies induce electronic deep-gap levels. Scenarios are discussed to account for shallow-gap levels observed experimentally.

No abstract