First-principles investigation of the ferroelectric, piezoelectric and nonlinear optical properties of LiNbO3-type ZnTiO3

The newly synthesized LN-type ZnTiO 3 (J. Am. Chem. Soc. 2014, 136, 2748) contains cations with the electronic configurations nd 10 (Zn 2+ : 3d 10 ) along with second-order Jahn-Teller (SOJT) nd 0 (Ti 4+ : 3d 0 ) cations. This is different from traditional ferroelectrics with the electric configurations of d 0 transition metal ions or/and lone pair electrons of ns 2 . Using a first-principles approach based on density functional theory, we investigate the electronic structure, zone-center phonon modes, piezoelectric and nonlinear optical properties of the LiNbO 3 -type ZnTiO 3 . The electronic structure indicates that this compound is a wide direct-band-gap insulator. The results reveal that this compound is a good ferroelectric material with a large spontaneous polarization of 90.43μC/cm 2 . The Raman scattering peaks of A 1 and E modes are assigned to their zone-center optical modes. Additionally, the large piezoelectric and nonlinear optical susceptibilities reveal that LiNbO 3 -type ZnTiO 3 is a high-performance lead-free piezoelectric and nonlinear optical crystal.