Electronic, Optical and Mechanical Properties of Ta Doped LiNbO3: Ab Initio Calculation

In this study, the electronic, optical and mechanical properties of LiNb1-xTaxO3 were investigated by ab initio method by adding tantalum (Ta) instead of niobium (Nb) with 0.1 doping step from x=0 to x=1 at different concentrations. The effects of Ta addition on the electronic structure of LiNbO3 were investigated. The results indicate that Ta doping results in an increase in the forbidden band gap of LiNbO3. The real and imaginary parts of the dielectric function of LiNb1-xTaxO3 were calculated and the optical transitions between the bands were determined. The second-order elastic constants of Ta doped LiNbO3 were calculated and the mechanical stability of the material was determined. In addition, the calculated elastic constants were used to determine the bulk modulus (B), shear modulus (G), Young's modulus (E), H_macro and H_micro hardness values. It was determined that the LiNb1-xTaxO3 material exhibited a transition from a ductile to a more brittle state with the addition of Ta.