Second harmonic generation imaging of local antiferroelectric-ferroelectric phase transitions in a PbZr O 3 thin film

Polar orders play a central role in modern technologies, spanning applications from information storage and energy harvesting to neuromorphic computing. While ferroelectric (FE) implementation into devices is more mature, the development of antiferroelectric (AFE)-based devices is still in its infancy. However, AFEs are emerging as promising candidates for multiple applications such as energy storage (supercapacitors), all-solid refrigeration (electrocaloric cooling) or thermal switches. In this work, we probe the transition between the antipolar and polar states in epitaxial layers of the prototypical antiferroelectric oxide, <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mi>PbZr</a:mi> <a:msub> <a:mi mathvariant="normal">O</a:mi> <a:mn>3</a:mn> </a:msub> </a:mrow> </a:math> . We discuss operando second-harmonic generation (SHG) imaging as a powerful tool, providing spatially resolved insights into the electric-field-induced AFE–FE phase transitions. This technique enables the mapping of local symmetry-breaking and phase coexistence during switching, offering a route to unravel the microscopic mechanisms governing AFE–FE transitions in such functional oxides.