Stress-induced phase transition and deformation behavior of BaTiO ₃ nanowires

In this paper, the electromechanically coupled behaviors of BaTiO ₃ nanowires are investigated by shell-model based molecular dynamics and proposed analytical models. Three-stage stress-strain and stress-polarization relations are found that are mainly originated from the existence of a mixed phase composition. A phase diagram in terms of wire diameters and axial stresses is constructed. Furthermore, the elastic modulus is found to decrease dramatically with the increase of diameter for the nanowire in paraelectric phase, while the piezoelectric coefficient of the ferroelectric phase is not very sensitive to the size. Besides, the size dependencies of hysteresis and butterfly loops are also revealed.