Effect of intrinsic point defects on the electronic and optical properties of Ho:BYF crystal

Abstract

First-principles methods have been applied to explore the effect of intrinsic point defects on the electronic and optical properties of Ho:BYF crystal. Among the intrinsic point defects in Ho:BYF crystal, fluorine vacancies (VF1, VF2, VF3) and interstitial defects (BaIn, YIn, FIn) have lower formation energy and more stable structure. The calculated electronic properties manifest that the new defect states appear and the overall electronic density of states shifts to the lower energy region. The principal absorption at around 0.613 eV (2 μm) of fluorine vacancies (VF1) occurs in the near-infrared range owing to the electronic transitions from the occupied f-orbitals of the Ho atoms to empty f-orbitals of neighboring Ho atoms. Therefore, there may be a 2 μm luminescence in the Ho:BYF crystal because of the interaction of doping Ho atom and fluorine vacancies defects (VF1).