Control of ordering in a polar skyrmion lattice through the ferroelectric proximity effect

Complex topological configurations are fertile ground for exploring emergent phenomena and exotic phases in condensed-matter physics. Topological solitons such as magnetic skyrmions have long drawn attention as stable quasi-particle-like objects, but the recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened the door for new length scales and electric-field manipulation. Functional phenomena can be distinct from those of normal ferroelectrics, with properties such as collective dynamics, chirality, and negative capacitance. Topologically nontrivial ferroelectric textures are uniquely possible and manipulable by careful control of thin film boundary conditions, allowing for the exploration of phase space and order-disorder transitions with atomic precision. Here, we show controlled ordering of polar skyrmions enabled through electrostatic coupling, controlled by the ferroelectric proximity effect in incipient ferroelectric SrTiO₃.