Electrostatic nano-mask patterned 180° domain walls in a ferroelectric film

Ferroelectric domain walls (FDWs) exhibit exotic structural and electronic properties, positioning them as a promising functional element for next-generation nanoelectronics. However, achieving the deterministic creation of FDWs with nanoscale precision and controlled polarization of domains remains a substantial challenge for the scalable FDW-device fabrication and circuit design. Here, we demonstrate a strategy for FDW engineering by tailoring the interfacial electrostatic profile. Using SrRuO₃ islands as "nano-masks," we spatially modulate the interfacial atomic termination to generate alternating positive and negative built-in electric fields. The boundaries where the electric field switches polarity drive the formation of 180° FDWs in BiFeO₃ thin films. This mechanism is validated through theoretical calculations and direct experimental observations. Furthermore, atomic-scale analysis reveals localized lattice distortions, structural chirality of the FDWs, as well as the edge effect of SrRuO₃ islands on the position precision of FDW nucleation. Our findings pave the way toward a scalable and controllable bottom-up FDW-growth technique for future FDW nanoelectronics.