Ferroelectric and nonlinear optical properties of the LiNbO3-type ZnGeO3 from first-principles study

Electronic structure, spontaneous polarization, piezoelectric, and nonlinear optical properties of the LiNbO3(LN)-type ZnGeO3 have been investigated based on the density functional theory. The electronic structure reveals that the LN and corundum-type ZnGeO3 are both direct-band-gap semiconductors. The results reveal that the LN-type ZnGeO3 is ferroelectric with a large spontaneous polarization of 63.59 μC/cm2. Although the LN-type ZnGeO3 and LiNbO3 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 ZnGenO3 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.

► Based on density functional theory, we have investigated its ferroelectric and nonlinear optical properties.
► This compound is ferroelectric with a large spontaneous polarization.
► Along the z-axis, the large polarization attributes to the symmetry breaking of the cations sequences including vacancies.
► In addition, the results reveal that this compound is a good lead-free piezoelectric and nonlinear optical crystal.