Reversible flexoelectric domain engineering at the nanoscale in van der Waals ferroelectrics
Heng Liu, Qinglin Lai, Jun Fu, Shijie Zhang, Zhaoming Fu, Hualing Zeng
Abstract
Abstract The universal flexoelectric effect in solids provides a mechanical pathway for controlling electric polarization in ultrathin ferroelectrics, eliminating potential material breakdown from a giant electric field at the nanoscale. One challenge of this approach is arbitrary implementation, which is strongly hindered by one-way switching capability. Here, utilizing the innate flexibility of van der Waals materials, we demonstrate that ferroelectric polarization and domain structures can be mechanically, reversibly, and arbitrarily switched in two-dimensional CuInP 2 S 6 via the nano-tip imprinting technique. The bidirectional flexoelectric control is attributed to the extended tip-induced deformation in two-dimensional systems with innate flexibility at the atomic scale. By employing an elastic substrate, artificial ferroelectric nanodomains with lateral sizes as small as ~80 nm are noninvasively generated in an area of 1 μm 2 , equal to a density of 31.4 Gbit/in 2 . Our results highlight the potential applications of van der Waals ferroelectrics in data storage and flexoelectronics.