LAUSR

Dipolar slices explain the origin of ferroelectricity in a material now used for memory devices The ferroelectrics community is witnessing one of those moments in which serendipity changes the course of science. The story of ferroelectric hafnia (HfO2) resembles that of Cinderella: Not invited to the polar dielectrics ball, nanoscale HfO2 was dismissed as not being a real ferrolectric, a material that has a switchable spontaneous polarization, despite the experimental evidence for this response. On page 1343 of this issue, Lee et al. (1) bring us closer to a real-life fairy tale ending with their theoretical calculations, which show that nanoscale HfO2 becomes a ferroelectric through a different mechanism. Polarization manifests in the form of two-dimensional (2D) slices separated by nonpolar spacers, associated with flat polar phonon bands that allow for homogeneous switching of electric dipoles.