Regensburg 2025 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 5: Instrumentation, Microscopy and Tomography with X-ray Photons, Electrons, Ions and Positrons

KFM 5.1: Vortrag

Montag, 17. März 2025, 15:00–15:15, H9

Simulation study of beam splitting of vortex electron beams inside crystals — •Christian Bick and Dorothee Hüser — Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Electron vortex beams have long been of interest for applications such as electron magnetic circular dichroism (EMCD), beam shaping and nanoparticle manipulation. They have attracted new attention with the recent development of an orbital angular momentum (OAM) sorter, theoretical developments in analysis of momentum transfer and as a quantum logic gate.

When propagating through a crystal, the vortex electron wave interacts with the asymmetric crystal potential, causing the wave to split into intensity centres around atomic columns, called channelling. This behaviour gives rise to a total OAM that can no longer be described by an integer vortex quantum number. In this simulation-based study we track the behaviour of electron beams inside different crystals. We show an in-depth analysis of the wave phase propagating through the crystal for different materials, focussing our research on beam splitting into intensity centres with their own OAM. This study was carried out using multislice simulations of the electron beam propagation through the crystal potential together with vector analysis to identify the local vortex centres.

Keywords: electron vortex beams; transmission electron microscopy; orbital angular momentum; elastic electron scattering