Kinetic control of ferroelectricity in epitaxial barium titanate thin film capacitors

Ferroelectricity is characterized by the presence of spontaneous and switchable macroscopic polarization, and understanding its scaling limits is crucial for fundamental research and technological innovation. Although indirect probes have confirmed ferroelectricity down to the unit-cell scale, practical applications demand direct electrical measurements on devices that overcome challenges such as leakage currents. Recent interest in low voltage switching electronic devices squarely puts the focus on the thickness limits of ferroelectricity in the most basic electronic device form, a parallel plate capacitor, specifically on the robustness of ferroelectric characteristics such as retention and endurance. Here, we demonstrate how precise manipulation of plasma plume kinetic energy during pulsed laser deposition can yield ferroelectric capacitor heterostructures exhibiting excellent bulk and interfacial quality, substantially reduced leakage currents, and a broad “growth window” at close to ultrathin limits. These heterostructures reveal unprecedented ferroelectric performance in thin films of the prototypical perovskite BaTiO3, including ultra-low switching voltages (<0.3 V), long retention times (>104 s), and high endurance (>1011 cycles). Our work demonstrates that materials engineering can push the envelope of performance for ferroelectric materials and devices at the thin limit and opens a direct, reliable, and scalable pathway to practical applications of ferroelectrics in ultra-low-voltage switches for logic and memory technologies.