Effects of Li+ and Nb5+ cationic sites on macroscopic properties of lithium niobate crystals

A comprehensive study on the role of Li+ and Nb5+ sites in a lithium niobate (LiNbO3) crystallographic frame using Pauling's rules, Abrahams' empirical model, the bond valence sum model and chemical bond method, is briefly summarized in the present paper. Some physical properties of LiNbO3 crystals such as calculated dielectric responses (including refractive indices and second order nonlinear optical coefficients), experimental ferroelectric Curie temperature Tc, and calculated spontaneous polarization Ps, are discussed in this connection. Our results clearly show that Li+ site can produce much stronger effects on these physical properties than Nb5+ site, which is helpful to the further development of various properties of LiNbO3 crystals.