First-principles optical spectra for the oxygen vacancy in YAlO3 crystal

Abstract

The defect formation energies of oxygen vacancies in YAlO3 crystal (YAP) with different charge states (0, +1, +2) are calculated using density functional theory. Advanced hybrid density functionals are employed to relieve the band edge problem (with Alkauskas’s method). The finite-size correction scheme (FNV) is adopted to align the defect formation energy containing artificial interactions between charged defects within the supercell approach. We have analyzed the structures and charge densities of defects with three charge states after the structure optimization. The stability of charged vacancies with respect to neutral one has been discussed. It turns out that Vo2+ is relative stable in most cases. At last, we give the accurate description of optical line shapes for F/F+ centers containing electron-phonon coupling. The results show that F+ centers play an important role in color changes in YAP.