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Martin Hájek

Publications and source records attributed to Martin Hájek.

2 recordsLinked to original sources
arXiv2026

Thermal diffuse scattering in TEM: complex absorptive potentials compared to the frozen phonon model

In transmission electron microscopy, electrons undergo inelastic scattering primarily through phonon excitations, known as thermal diffuse scattering. To capture the inelastic scattering effects on the elastic scattering components, absorptive effects must be included in the modeling of electron propagation, accounting for the gradual depletion of the elastic channel of the electron beam. Several approaches to modeling this absorption exist. In this paper, we compare the widely used complex absorptive potentials method to the more elaborate frozen phonon model, based on correlated atomic motion and on the Einstein model of atomic motion.

cond-mat.mtrl-sci↗
arXiv2024

Efficient nanoscale imaging of solid-state phase transitions by transmission electron microscopy demonstrated on vanadium dioxide nanoparticles

We present annular dark field scanning transmission electron microscopy (ADF-STEM) as an efficient, fast, and non-destructive nanoscale tool for monitoring solid-state phase transition. Using metal-insulator transition in vanadium dioxide nanoparticles as an example, we characterize lattice and electronic signatures of the phase transition using analytical transmission electron microscopy including diffraction and electron energy-loss spectroscopy. We demonstrate that ADF-STEM shows a clear contrast across the transition, interpreted with the help of convergent electron beam diffraction as stemming from the crystal-lattice modification accompanying the transition. In addition, ADF-STEM utilizes 3--6 orders of magnitude lower electron dose when compared to electron microscopy techniques able to reveal the phase transition with the same spatial resolution and universality. The benefits of ADF-STEM are emphasized by recording a full hysteresis loop for the metal-insulator transition of a single vanadium dioxide nanoparticle. Our study opens the prospect for fast, non-destructive, large-area and nanoscale characterization of solid-state phase transitions.

cond-mat.mtrl-sci↗