Analytical prediction of size-induced ferroelectricity in BaO nanowires under stress

We predict that a ferroelectric phase can be induced in otherwise nonferroelectric binary oxides like BaO, EuO and ${\text{Er}}_2{\text{O}}_3$ by a strong enough stress $\sigma \sim \mu /R$ present under the curved surface in nanowires due to intrinsic surface stress $\mu$. Our analytical calculations performed within the Landau-Ginzburg-Devonshire theory prove that BaO nanowires of radius $R\sim \left(1–10\right)\text{nm}$ can be ferroelectric at room temperatures with spontaneous polarization values $\sim 0.5\text{C}/{\text{m}}^2$ for typical surface stress coefficients $\mu \sim \left(10–50\right)\text{N}/\text{m}$. The same phenomena could lead to high temperature magnetoelectric effect in nanosystems of magnetic binary oxides. DOI: http://dx.doi.org/10.1103/PhysRevB.81.092101 © 2010 The American Physical Society