AP Seminar - Probing the Properties and Dynamic Behaviors of Nanostructured Materials with Atomic Resolution in Real-Time

Recent advancements in aberration-correction, electron detection, and in situ techniques have propelled transmission electron microscopy (TEM) and spectroscopy into the realm of real-time, atomic-scale investigations of material structure, properties, and dynamics. In this talk, I will discuss our recent progress in developing and applying advanced electron microscopy and spectroscopy methods to visualize the atomic structure and functional properties of materials, alongside observing their dynamic responses to external forces and varying environmental conditions. We achieve direct imaging of local electric fields, charge distributions, polarization, and the behavior of domain walls in ferroelectrics [1-2]. Utilizing newly developed spatial and angle-resolved electron energy-loss spectroscopy (EELS), we uncover novel vibrational modes and emergent phonon behaviors at single defects [3] and interfaces [4-5], enabling nanoscale mapping of phonon momentum and heat flow. These insights provide an unprecedented view into the mechanisms governing the functional behavior of nanostructured materials.

References:

1. Li et al., “Real-time studies of ferroelectric domain switching: a review,” Rep. Prog. Phys. 82, 126502 (2019).
2. Gao et al., “Real-space charge-density imaging with sub-ångström resolution by four-dimensional electron microscopy,” Nature 575, 480–484 (2019).
3. Yan et al., “Single-defect phonons imaged by electron microscopy,” Nature 589, 65–69 (2021).
4. Gadre et al., “Nanoscale imaging of phonon dynamics by electron microscopy,” Nature 606, 292–297 (2022).
5. Yang et al., “Phonon modes and electron–phonon coupling at the FeSe/SrTiO₃ interface,” Nature (2024). https://doi.org/10.1038/s41586-024-08118-0