Skyrmion nanodomains in ferroelectric-antiferroelectric solid solutions

Polar skyrmions have demonstrated rich physics and exotic properties for developing novel functionalities. However, so far, skyrmion nanodomains exist only in a few material systems, such as ferroelectric/dielectric superlattices, free-standing PbTiO₃/SrTiO₃ epitaxial bilayers and ultrathin Pb(Zr,Ti)O₃/SrTiO₃/Pb(Zr,Ti)O₃ sandwiches. These heterostructures are fabricated with elaborately designed boundary conditions to meet the delicate energy balance for stabilizing topological phases. This requirement limits the broad applications of skyrmions in electronic devices. Here we show widespread skyrmion nanodomains in ferroelectric-antiferroelectric solid solutions, composed of ferroelectric PbTiO₃ and one antiferroelectric PbSnO₃ (Pb(Ti_1-xSn_x)O₃), PbHfO₃ (Pb(Ti_1-xHf_x)O₃) or PbZrO₃ (Pb(Ti_1-xZr_x)O₃). The skyrmionic textures are formed by engineering dipole-dipole and antiferrodistortive-dipole couplings in competition between ferroelectric and antiferroelectric polar orderings, allowing the stabilization of topological phases. A phase diagram is built for the three solid solution series, revealing the stabilization regions of skyrmion nanodomains. In addition, the non-trivial domains also exhibit improved switching character, reversible writing/erasure and long-term retention for the electrical manipulation of polar configurations. These findings open an avenue for the investigation and exploitation of polar skyrmions in ferroelectric-based materials, providing opportunities in topological electronics.