Recently, researchers from the Shanghai Institute of Ceramics at the Chinese Academy of Sciences, led by Dr. Xu Fangfang and Dr. Wang Genshui, collaborated to construct a theoretically predicted triple-period modulated structure in lead zirconate (PbZrO3) thin films by inducing lattice mismatch-induced phase separation. The volume fraction of this structure can be controlled by the thickness of the film. The research findings have been published in "Nature Communications."
Antiferroelectric perovskite oxides exhibit rich modulated phase sequences, where under electric field excitation, reversible or irreversible transitions between antiferroelectric and ferroelectric states occur, accompanied by significant changes in charge, volume, or heat. This phenomenon serves as a crucial physical basis for energy storage, conversion, and driving applications. Currently, there is widespread debate among international scholars regarding the ground-state structure of PbZrO3-based antiferroelectric materials, with various theories proposing multiple polarization sequences with similar energies that compete with each other.
The research team experimentally discovered a unique coexisting phase structure of a triple modulated period subferroelectric phase and a classic fourfold modulated period antiferroelectric phase. They revealed that the triple modulated period subferroelectric phase gradually increases with the thickness of the film, mainly due to the presence of reverse domain boundaries. The majority of the substrate's compressive stress on the film is released through the formation of mismatched dislocations at the film/substrate interface. Factors such as mismatched dislocations, film thickness, and thermal expansion coefficient determine the density of reverse domain boundaries within the film. By controlling the formation of reverse domain boundaries, the volume fraction of the triple-period subferroelectric phase can be regulated using film thickness.
New triple-periodic polarization structure and its formation mechanism in PbZrO3-based antiferroelectric materials. Image source: Nature Communications.
Related paper information: https://doi.org/10.1038/s41467-024-47776-6
