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

Abstract

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.