Magnetic and optical properties of N-doped, Fe-doped and (N, Fe)-codoped anatase TiO2

Electronic structure, magnetic and optical properties of N-doped, Fe-doped and N, Fe-codoped anatase TiO2 have been investigated by using first-principles calculations. Both N-doped and Fe-doped anatase TiO2 exhibit ferromagnetic semiconductors, while N, Fe-codoped one manifests metallic nature with antiferromagnetic ground state. The optical absorption spectrum for all the doped models extends the optical absorption to the visible-light region. Especially, N, Fe-codoped anatase TiO2 presents the highest absorption coefficient during the visible-light energy range (1.63–3.1 eV). Furthermore, the ultraviolet absorption is also enhanced, particularly for N-doped model.