Finite-size effects in BaTiO3 nanowires

TL;DR

This study investigates how the ferroelectric properties of BaTiO3 nanowires depend on size, revealing a critical diameter below which ferroelectricity vanishes and how strain can restore it.

Contribution

The paper provides first-principles insights into size effects and strain-induced ferroelectricity in BaTiO3 nanowires, identifying a critical diameter and mechanisms for property recovery.

Findings

Ferroelectric distortion disappears below ~1.2 nm diameter.

Surface atomic coordination affects ferroelectricity.

Tensile strain can recover ferroelectric distortion.

Abstract

The size dependence of the ferroelectric properties of BaTiO$_3$ nanowires is studied from first-principles. We show that the ferroelectric distortion along the wire axis disappears below a critical diameter of about 1.2 nm. This disappearance is related to a global contraction of the unit cell resulting from low atomic coordinations at the wire surface. It is shown that a ferroelectric distortion can be recovered under appropriate tensile strain conditions.