Low-Field-Driven Domain Wall Motion in Wurtzite Ferroelectrics

Wurtzite-type nitride ferroelectrics emerge as a breakthrough platform for silicon-compatible nonvolatile memory technology. However, the inherent polarization reversal mechanisms involving diatomic displacements introduce complex domain dynamics and elevate energy barriers, manifesting as excessive coercive fields (E_c) and pronounced wake-up effects that hinder reliable device operation. Here, these challenges are resolved by enabling the low-field-driven domain wall motion in representative wurtzite ferroelectrics (Al_0.75Sc_0.25N). In situ transmission electron microscopy measurements reveal that polarization switching proceeds via preferential domain-wall transverse propagation perpendicular to the [0001] axis, preceding longitudinal propagation along the [0001] axis. First-principles simulations quantify a striking 98% reduction in energy barrier for transverse migration (0.00188 eV f.u^-1). Compared to longitudinal motion (0.092 eV f.u^-1). This switching kinetic fundamentally challenges the conventional Kolmogorov-Avrami-Ishibashi model. By controlling nucleation polarity to promote the transverse motion of the domain wall, E_c is reduced by 25%, with a high remanent polarization maintained and wake-up effects eliminated across 6-inch films. The methodology establishes a universal design principle for manipulating polarization switching in wurtzite ferroelectrics, paving the way for integrated low-energy, high-stability, uniformly-performing ferroelectric devices in large-scale complementary metal oxide semiconductor (CMOS) architectures.