Ferroelectric and nonlinear optical properties of the LiNbO 3-type ZnGeO 3 from first-principles study

Abstract

Electronic structure, spontaneous polarization, piezoelectric, and nonlinear optical properties of the LiNbO 3(LN)-type ZnGeO 3 have been investigated based on the density functional theory. The electronic structure reveals that the LN and corundum-type ZnGeO 3 are both direct-band-gap semiconductors. The results reveal that the LN-type ZnGeO 3 is ferroelectric with a large spontaneous polarization of 63.59 μC/cm 2. Although the LN-type ZnGeO 3 and LiNbO 3 belong to the same point group 3m, their piezoelectric and nonlinear optical susceptibilities show the different tensor forms. According to the predictive results, the large piezoelectric constants and NLO susceptibilities reveal that the LN-type ZnGenO 3 would be a candidate for a high-performance lead-free piezoelectric and nonlinear optical crystal, which will avoid the environmental toxicity problem of the lead-based materials.