Guest Seminar - SPM in Crystals World: More Than Just Imaging - Dr. Irit Rosenhek-Goldian

Abstract

Scanning probe microscopy (SPM), and particularly atomic force microscopy (AFM), has evolved far beyond high-resolution surface imaging. Today, it provides a powerful platform for studying nanoscale structure, mechanics, dynamics, and functional properties in a wide range of materials.

In this talk, I will highlight how SPM contributes to understanding crystal growth, crystal mechanics, and structure–property relationships. Beyond three-dimensional topographic imaging, AFM enables quantitative measurements of mechanical properties such as elastic modulus and hardness, as well as direct visualization of dynamic surface and interface processes. Recent developments in our unit, including correlative AFM-SEM platforms, fast scanning capabilities, further expand the potential of AFM for efficient, accurate, and dynamic nanoscale characterization.

Several examples will demonstrate the power of SPM in the crystal world. In halide perovskite single crystals, AFM-based nanoindentation reveals how humidity affects surface and bulk mechanical properties, showing an unusual decrease in hardness alongside an increase in elastic modulus. In mixed-dimensional CsPbBr₃/ReSe₂ heterostructures, correlative nanoscale analysis helps reveal how substrate anisotropy governs epitaxial growth and interfacial behavior. In metal-organic framework crystals, correlative AFM-SEM imaging uncovers how amorphous particles attach, crystallize, and merge into growing crystals, leading to complex multidomain morphologies while preserving single crystallinity. In molecular crystals such as theophylline, AFM provides insight into classical molecule-by-molecule growth, showing how lattice interactions and supersaturation can guide crystal morphology and even enable regeneration after damage.

Finally, AFM-based mechanical measurements will also be discussed in the context of bio-mineralized diatom silica cell walls, where shell geometry and elasticity play key roles in cell-size regulation. Together, these examples demonstrate that SPM is much more than an imaging tool: it is a versatile approach for revealing nanoscale mechanisms of crystal growth, mechanics, anisotropy, deformation, and functional behavior across synthetic and biological crystalline systems.