First-principles study of the ferroelectric and nonlinear optical properties of the LiNbO3-type ZnSnO3

Electronic structures, spontaneous polarization, dynamical and nonlinear optical (NLO) properties of polar oxide ZnSnO3 with LiNbO3 (LN)-type structure have been investigated in the framework of density functional theory. By analyzing the Born effectives of LN-type ZnSnO3, we find that Z* of Zn atoms show relatively large anomalous behavior. The spontaneous polarization is attributed to the large displacement of Zn atoms because of the mixed ionic-covalent character between the Zn-O bonds. The optical dielectric tensor is nearly the same; however the static dielectric tensor shows strongly anisotropy. Furthermore, the nonlinear optical properties are calculated by using 2n + 1 theorem applied to an electric-field dependent energy functional. The large dielectric constants and NLO susceptibilities indicate that the LN-type ZnSnO3 would be a candidate as a high-performance dielectric and nonlinear optical material.