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

Abstract

Stable ferroelectricity with high transition temperature in nanostructures is needed for\rminiaturizing ferroelectric devices. Here, we report the discovery of the stable in-plane\rspontaneous polarization in atomic-thick tin telluride (SnTe), down to a 1–unit cell (UC) limit.\rThe ferroelectric transition temperature Tc of 1-UC SnTe film is greatly enhanced from the bulk\rvalue of 98 kelvin and reaches as high as 270 kelvin. Moreover, 2- to 4-UC SnTe films show\rrobust ferroelectricity at room temperature. The interplay between semiconducting properties\rand ferroelectricity in this two-dimensional material may enable a wide range of applications in\rnonvolatile high-density memories, nanosensors, and electronics.