Asymmetric screening of the depolarizing field in a ferroelectric thin film

A first-principles-based approach is developed to mimic the (asymmetric) screening of the depolarizing field at the top surface of ferroelectric ultrathin films. Varying the magnitude of this one-side screening (i) results in the formation of different kinds of periodic nanostripe domain patterns, including original ones that are highly asymmetric and that can be thought of as connecting (and generalizing) the traditional Landau-Lifshitz and Kittel models of dipolar domains, and (ii) leads to a change in the domain's period, suggesting that the asymmetric screening of the depolarizing field is responsible for the existence of two recently observed nanostripe phases.