fig8

Figure 8. Emergence of ferroelectricity in ultrathin films of otherwise non-ferroelectric SrTiO₃. (A) Schematics illustrating the effect of polar nanoregions based on thickness. In thicker films, polar nanoregions are not effectively aligned, whereas in thinner films, they align well. (B) Inverted ABF-STEM image and corresponding polarization mapping. Polar nanoregions are well visualized. Reproduced with permission^[14]. Copyright 2015, American Association for the Advancement of Science.