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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 8: Microscopy and Tomography with X-ray Photons, Electrons, Ions and Positrons

KFM 8.1: Talk

Monday, March 18, 2024, 12:10–12:30, TC 010

High angular momentum vortex electron beams in crystals — •Christian Bick and Dorothee Hüser — Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Since the introduction of beams with an orbital angular momentum (OAM), commonly known as vortex electron beams, into scanning transmission electron microscopy (STEM), they have been used in electron magnetic circular dichroism (EMCD) and nanoparticle manipulation [1]. Understanding the behaviour of these beams in material can help to better interpret experimental results. Previous studies have shown that vortex electron beams change their angular momentum as they propagate through the crystal. This change can be modelled by a superposition of eigenstates of the OAM operator [2,3].

We present a simulation-based study on the behaviour of higher order angular momentum vortex electron beams in crystalline material. The study is based on multislice calculations, which are commonly used in simulating STEM measurements.

[1] S. M. Lloyd, M. Babiker, and J. Yuan, Phys. Rev. A 86, 023816 (2012).

[2] S. Löffler and P. Schattschneider, Acta Crystallogr. A 68, 443 (2012).

[3] A. Lubk et al., Phys. Rev. A 87, 033834 (2013).

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