First-principles study on the effects of point vacancies on the spectral properties of MgAl2O4

The electronic structures and absorption spectra of the perfect MgAl2O4 spinel and the MgAl2O4 containing various vacancies have been studied by using DFT code in VASP package. The optical transition models induced by oxygen vacancy are predicted. Our results show that the absorption peak at 5.3 eV is due to the neutral oxygen vacancy VO0. Both 3.2 and 4.75 eV peaks are attributed to the 1+ charged oxygen vacancy VO1+. And more, our absorption spectra also indicate that the experiment observed red shift in UV transparent spectra of nano-ceramic MgAl2O4 is induced by the various color centers of oxygen vacancies.

Research highlights
► Theoretical calculation of various point vacancies in MgAl2O4 spinel.
► The electronic structures and absorption spectra have been studied.
► The optical transition models induced by oxygen vacancies are predicted.
► Gives an explanation to the experimental optical properties of the MgAl2O4 nano-ceramics.