Oxygen migration enables ferroelectricity on nanoscale

Hafnium-based thin films, with a thickness of only a few nanometres, show an unconventional form of ferroelectricity. This allows the construction of nanometre-sized memories or logic devices. However, it was not clear how ferroelectricity could occur at this scale. A study has now shown how atoms move in a hafnium-based capacitor: migrating oxygen atoms (or vacancies) are responsible for the observed switching and storage of charge.