Tuning Ferroelectric Properties of Barium Titanate by Lateral Strain: A Molecular Dynamics Simulation Study

BaTiO3 (BT), a lead-free ferroelectric material, is employed in energy-conversion devices, including actuators and capacitors. However, its ferroelectric properties, such as the piezoelectric coefficient and Curie temperature, fall short of those of harmful lead-based ferroelectrics, such as Pb(Zrx, Ti1-x)O3. In this study, a BT crystal is examined under biaxial strain (i.e., strain in the a- and b-directions of the unit cell) to investigate the alterations in its ferroelectric properties. The piezoelectric coefficient, Curie temperature, polarization magnitude, and coercive electric field are calculated under varying biaxial strains using molecular dynamics simulations. The simulations utilize a core-shell-type interatomic potential developed from first-principles electronic structure calculations. In the findings, it is revealed that 1) the Curie temperature, polarization magnitude, and coercive electric field increase, whereas the piezoelectric coefficient in the c-direction decreases under biaxial compression; 2) modifications in the ferroelectric properties depend on the area of ab-plane and not on its aspect ratio. Comprehensive analyses of the Ti-displacement distribution offer microscopic insights into strain-induced shifts in ferroelectric properties. BaTiO3 (BT) is a lead-free ferroelectric material used in energy-conversion devices. However, its properties do not match those of lead-based ferroelectrics. Alterations in the ferroelectric properties of BT under biaxial strains, including the Curie temperature, piezoelectric coefficient, and cohesive electric field, are investigated using molecular dynamics simulations. The microscopic mechanisms underlying property changes are explained through Ti-displacement analyses.image (c) 2023 WILEY-VCH GmbH