The optical properties of lead-free KTa_1/2Nb_1/2O ₃:M where M = Li, Na, H, Cu, Zn

First principle calculations are used to investigate the effect of doped Li, Na, H, Cu and Zn atoms on the optical properties of paraelectric KTa _1/2Nb_1/2O₃ (KTN). The calculated results show that Li and Na have little effect on the optical properties of KTN, in agreement with experimental data. However, H, Cu and Zn atoms all have strong influence on the electronic structure and optical properties of KTN. KTN:H may be not suitable for optical applications because of strong absorption, whereas both KTN:Cu and KTN:Zn have excellent optical performance. We predict that KTN:Zn is a conducting optical crystal, which may be applied in the field of optical devices.