Discovery of robust in-plane ferroelectricity in atomic-thick SnTe

TLDR

In ferroelectrics, reducing thickness typically lowers the Curie temperature at which spontaneous polarization appears. The authors fabricated high‑quality SnTe thin films and measured their ferroelectric transition temperatures, finding them higher than bulk values. Even monolayer SnTe films exhibit a transition temperature above room temperature, indicating promise for ultra‑compact ferroelectric devices. Chang et al., Science, p.

Abstract

Thinning a ferroelectric makes it better As a ferroelectric material becomes thinner, the temperature below which it develops its permanent electrical polarization usually decreases. Chang et al. fabricated high-quality thin films of SnTe that, in contrast to this conventional wisdom, had a considerably higher transition temperature than that of the material in bulk (see the Perspective by Kooi and Noheda). This was true even for single-unit cell films, whereas only slightly thicker films became ferroelectric above room temperature. This finding may enable the miniaturization of ferroelectric devices. Science , this issue p. 274 ; see also p. 221