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

Jing Zhang,Bin Xu,San-Huang Ke,Zhen Qin,Yu-Sheng Wang

doi:10.1038/s41598-019-53986-6

Abstract

The newly synthesized LN-type ZnTiO3 (J. Am. Chem. Soc. 2014, 136, 2748) contains cations with the electronic configurations nd10 (Zn2+: 3d10) along with second-order Jahn-Teller (SOJT) nd0 (Ti4+: 3d0) cations. This is different from traditional ferroelectrics with the electric configurations of d0 transition metal ions or/and lone pair electrons of ns2. 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 LiNbO3-type ZnTiO3. 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/cm2. The Raman scattering peaks of A1 and E modes are assigned to their zone-center optical modes. Additionally, the large piezoelectric and nonlinear optical susceptibilities reveal that LiNbO3-type ZnTiO3 is a high-performance lead-free piezoelectric and nonlinear optical crystal.

Highlights

In recent years, noncentrosymmetric (NCS) compounds have attracted great interest in physics and material science because of their symmetry-dependent ferroelectric, piezoelectric and second-order nonlinear optical (NLO) properties, etc[1,2]
In 2014 a new NCS compound, the LN-type ZnTiO3, was synthesized by Inaguma et al under high temperature and high pressure[14]. Their results show that LN-type ZnTiO3 has a large spontaneous polarization and greater second harmonic generation (SHG) response compared to LiNbO3 and LN-type ZnSnO3
First-principles calculations based on density functional theory (DFT) play an important role in meeting the needs of experimenters because they can accurately predict the properties of new materials at the atomic scale

Summary

Introduction

Noncentrosymmetric (NCS) compounds have attracted great interest in physics and material science because of their symmetry-dependent ferroelectric, piezoelectric and second-order nonlinear optical (NLO) properties, etc[1,2]. In 2014 a new NCS compound, the LN-type ZnTiO3, was synthesized by Inaguma et al under high temperature and high pressure[14]. Their results show that LN-type ZnTiO3 has a large spontaneous polarization and greater second harmonic generation (SHG) response compared to LiNbO3 and LN-type ZnSnO3. In order to study the intrinsic correlation from the paraelectric to ferroelectric phase transition, we have investigated the zone-center phonon modes of the ilmenite, perovskite and LiNbO3-type ZnTiO3 phases, respectively. Since the piezoelectric and nonlinear optical properties of this type of novel material with nd[10] and SOJT nd[0] cations have not been investigated previously, our calculations provide an important complement to experimental research

Methods

Results

Conclusion