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 Er₂O₃ by a strong enough stress σ~μ/R present under the curved surface in nanowires due to intrinsic surface stress μ. Our analytical calculations performed within the Landau-Ginzburg-Devonshire theory prove that BaO nanowires of radius R~(1--10) nm can be ferroelectric at room temperatures with spontaneous polarization values ~0.5 C/m² for typical surface stress coefficients μ~(10--50) N/m. The same phenomena could lead to high temperature magnetoelectric effect in nanosystems of magnetic binary oxides.