Strain effect on ferroelectric behaviors of BaTiO₃ nanowires: A molecular dynamics study

In this paper, a molecular dynamics method is utilized to investigate the strain effect on the polarization distribution, piezoelectric coefficient, and hysteresis behaviors of BaTiO₃ nanowires. The axial polarization changes almost linearly with the strain over a relatively large range, and the ferroelectricity vanishes under a critical compressive strain. With the nanowire becoming thicker, the piezoelectric coefficient increases, and approaches its counterpart for bulk material when the diameter is larger than 2.4nm. It is also revealed that a pre-tension strain can induce the emergence of a stepwise hysteresis loop while a pre-compression strain can lead to the disappearance of the stepwise shape. Furthermore, the strain effect and size effect are found to play some equivalent roles in the ferroelectric properties of BaTiO₃ nanowires.