The Electronic Structures and Optical Properties of Substituted Rare-Earth Manganite Tb_1?xYb_xMnO₃

The electronic structures and optical properties of Tb_1?xYb_xMnO₃ as a function of Yb element content x are investigated by employing the first-principles method. The calculation results indicate that the electronic states associated with the Yb element are dominated gradually and the inner electronic states move to the lower energy level with the increasing x. The dielectric function and other optical properties of Tb_1?xYb_xMnO₃ such as the reflectance spectra are obtained and the results indicate that the static dielectric function reaches a maximum at about x=0.75, while the fitting expression predicts a maximum when x=0.69. In addition, it is found that one peak appearing at about 3.60 eV in the reflectance spectra of TbMnO₃ is driven to shift linearly towards higher energy level with the increasing x. However, another peak at about 29.63 eV moves nonlinearly in the same situation.