Influence of Tm, Ho and Er dopants on the properties of Yb activated ZnTiO3 perovskite: a density functional theory insight

Ab initio density functional theory calculations were employed to investigate the effect of Tm, Ho and Er substitutional dopants on the electronic and optical properties of Yb activated hexagonal zinc titanate (Yb:ZnTiO3). The Zn site was found to be the energetically favoured substitutional dopant site both for Yb activation and also Tm, Ho and Er substitutional doping. Among the different growth conditions, the Zn-rich condition was found to favour both Yb activation as well as Tm, Ho and Er substitutional doping. From the calculated substitutional energies, substitutional doping was found to be spontaneous in nature and the Yb-X (X = Tm, Ho, Er) complex was found to be stable only in the case of Yb-Tm and Yb-Ho doping. A red-shift in the band gap was observed upon the introduction of both the activator as well us the dopants resulting from theirf-orbitals. Significant changes in the optical absorption spectra in the lower frequency range (<3.143 eV) for all the considered case were also observed. A ferro-magnetic ground state was realized in the Yb-X dopant configurations. This study provides significant insights on the versatile ZnTiO3 compound for application in the area of magneto-optics.