Giant activated ferroelectric polarization in pristine anti-ferroelectric ZrO2 thin films

Ferroelectric fluorite oxides like hafnium (HfO2)-based materials are considered to be one of the most potential candidates for nowadays large-scale integrated-circuits (ICs). While zirconia (ZrO2)-based fluorites materials, which holds the same structure, is usually thought to be anti- or week ferroelectricity. We reported on an emergent giant ferroelectric remanent polarization (Pr) amounted to 53 μC/cm2 in orthorhombic ZrO2 growing on (110) SrTiO3 at room temperature. The robust ferroelectricity observed in ZrO2 is attributed to an irreversible orthorhombic anti-ferroelectric to a ferroelectric phase transition, facilitated by applying an electric field, particularly noticeable when the temperature is lowered to 77 K. This approach to reveal the intrinsic ferroelectricity in pure ZrO2 thin films, offers the new pathway to understand the origin ferroelectricity in fluorite oxides.