Finite-size effects in BaTiO 3 nanowires

The size dependence of the ferroelectric properties of BaTiO 3 nanowires is studied from first principles. We show that the ferroelectric distortion along the wire axis disappears below a critical diameter of about 1.2 nm. This disappearance is related to a global contraction of the unit cell resulting from low atomic coordinations at the wire surface. It is shown that a ferroelectric distortion can be recovered under appropriate tensile strain conditions. © 2006 American Institute of Physics. DOI: 10.1063/1.2186104