Electronic structure of Eu2+-doped SrAl2O4 using modified Becke–Johnson exchange potential

The optimized electronic structure of Eu2+-doped SrAl2O4 is calculated by using the modified Becke–Johnson potential combined with the local density approximation. The calculated minimum energy gap of SrAl2O4 is 6.9 eV, which is close to the experimental value (~6.5 eV). When a Eu atom replaces one of the Sr atoms, Eu 4f majority-spin states appear in the forbidden gap of SrAl2O4, which is estimated to be 5.5 eV above the valence band maximum. Considering spin–orbit coupling, Eu 4f majority-spin states decompose into two energy states and Eu 4f minority-spin states also appear in the band gap of SrAl2O4.