Heidelberg 2015 – wissenschaftliches Programm

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SYTL: Symposium Interactions between Twisted Light and Particles

SYTL 2: Symposium on interactions between twisted light and particles II (SYTL)

SYTL 2.1: Hauptvortrag

Freitag, 27. März 2015, 14:30–15:00, C/gHS

Electron vortex beams: Twisted matter waves — •Peter Schattschneider — Vienna University of Technology, 1040 Vienna, Austria

After the discovery of vortex electrons in 2010, free electrons with topological charge can now be routinely created in the electron microscope. Such vortices are characterized by a spiralling wavefront and a phase singularity at the center, similar to optical vortices that were described by Nye & Berry in 1974. Owing to their short wavelength, these matter waves can be focused to atomic size. Another novel aspect is their magnetic moment, quantized in multiples of the Bohr magneton, independent of the electron spin. These features make electron vortices extremely attractive as a nanoscale probe for solid state physics.

Although the theory of electron vortices in free space is well understood, interaction with fields or matter is more involved. Experimentally, a non-classical rotation mechanism in magnetic fields was found. It is caused by the Landau-Zeeman phase, analogous to the Berry phase causing rotation of optical beams. Nanocluster manipulation, breaking of rotational symmetry to distinguish enantiomeres, and detection of spin polarisation of single atomic columns was demonstrated. Electron vortices could serve as tweezers to move or rotate single atoms or molecules, or to detect sub-meV energy differences in the electron microscope.

Acknowedgements: The author thanks many colleagues for fruitful discussions. The financial support of the Austrian Science Fund (I543-N20) is gratefully acknowledged.