抄録
Ab nitio (first-principles) density-functional theory calculations were carried out in order to investigate ferroelectricity at twist boundary in PbTiO_3. Ferroelectric distortions at the Σ5 twist boundary are enhanced compared to those of the bulk. The effect of twist boundary structure on ferroelectricity ranges within 12 A. Such a local change in ferroelectricity stems from the strengthened Pb-O bond at the twist boundary. The applied tensile strain perpendicular to the boundary tends to enhance the ferroelectricity.
