Phase transition in Hf _0.5 Zr _0.5 O ₂ ferroelectric thin film induced by metal–insulator transition of VO ₂

Abstract HfO 2 ‐based ferroelectric thin films have attracted attention in diverse applications, including nonvolatile memory, energy storage, and compute‐in‐memory technologies. Controlling the transition between polar orthorhombic and nonpolar tetragonal phases in HfO 2 is of particular interest; however, it remains a challenge owing to the comparable phase energies of these structures. In this study, we engineered an Hf 0.5 Zr 0.5 O 2 (HZO)/VO 2 heterostructure, leveraging the reconfigurable interfacial strain that arises during the metal–insulator transition (MIT) in the VO 2 layer. A transformation in the hysteresis loops from ferroelectric to antiferroelectric‐like behavior was observed within the heterostructure as the temperature approaches the MIT point of VO 2 . This orthorhombic‐to‐tetragonal phase transition in the HZO layer was attributed to the strain induced by the structural transformation of VO 2 from a low‐temperature monoclinic phase to a high‐temperature tetragonal phase, as confirmed using in situ transmission electron microscopy. This paper presents a novel approach for phase control in HfO 2 ‐based thin films, paving the way for advanced material design and device engineering.