Nanoscale Imaging of Polarization and Ion Distributions in Functional Materials

Ions form the fundamental building blocks of most ceramic materials, where positive and negative ions are arranged as neighbors, primarily bonded through ionic interactions at the atomic scale. Additionally, certain polymeric and semiconductor materials contain mobile ions capable of diffusing in and out of the material matrix. In ferroelectric materials, polarization charges are typically compensated by an equal amount of oppositely charged surface screening charges under ambient conditions. Therefore, visualizing the spatial distribution, charge state, and dynamics of both ions and polarization is critical for advancing our understanding of the electrochemical properties of functional materials.
Here, I will introduce our recent research on advanced imaging techniques for probing ferroelectric polarization. We employ contrast mechanisms such as piezoelectric strain, screening charges, and friction coefficients as markers to visualize polarization at the nanoscale. I will also discuss how these techniques contribute to the development of energy harvesting devices and improvements in chemical mechanical polishing processes. Furthermore, I will present our work on imaging ionic species and charged defects using markers like electrochemical strain and local electric fields to map ion distributions. Finally, I will illustrate how imaging ion and electron conduction pathways provides insights into the nanoscale behavior and performance of battery materials.
Co-sponsored by: Yi Li
Speaker(s): Prof. Seungbum Hong,
Virtual: https://events.vtools.ieee.org/m/502555