Study on the electronic structures and the optical properties of the Mg-doped LiBaF3 crystal

The most possible substituting positions of impurity magnesium ions in LiBaF3 crystal are studied using the general utility lattice program (GULP). The electronic structures of Mg-doped LiBaF3 crystal are studied within the framework of the fully relativistic self-consistent Dirac-Slater theory using DV-Xα software. It is predicted that the most possible defect model is the [MgLi·+Li′Ba] in the Mg: LiBaF3 crystal, which exhibits donor level in the forbidden band. The optical transition energy from the Mg 3s state to the Ba 5d state is 2.975 eV, which is very close to the experimental result. It is indicated that the 420 nm absorption band originates from [MgLi·+Li′Ba] and the presence of the 510 nm luminescence band is related to the defect cluster [MgLi·+Li′Ba] in the Mg:LiBaF3 crystal too.