Toroidal Ferroelectricity in PbTiO3 Nanoparticles

STACHIOTTI, MARCELO; SEPLIARSKY. MARCELO

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2011 vol. 106 p. 137601 - 137601

0031-9007

We report from first-principles-based atomistic simulations that ferroelectricity can be sustained inPbTiO3 nanoparticles of only a few lattice constants in size as a result of a toroidal ordering. We find thatsize-induced topological transformations lead to the stabilization of a ferroelectric bubble by the align-ment of vortex cores along a closed path. These transformations, which are driven by the aspect ratio ofthe nanostructure, change the topology of the polarization field, producing a rich variety of polarconfigurations. For sufficiently flat nanostructures, a multibubble state bridges the gap between 0Dnanodots and 2D ultrathin films. The thermal properties of the ferroelectric bubbles indicate that this stateis suitable for the development of nanometric devices.