Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Poster Monday: Solid-Liquid Interfaces

O 20.7: Poster

Montag, 5. September 2022, 18:00–20:00, P4

Phase-shifting electron holography in an environmental TEM — •Ulrich Ross¹, Jonas Lindner², Tobias Meyer², Michael Seibt¹, and Christian Jooss² — ¹IV. Physik Georg-August Universität Göttingen — ²IMP Georg-August Universität Göttingen

Off-axis electron holography is a phase reconstruction technique which enables access to the complex exit-wave of thin samples. Information on the phase and amplitude of the exit wave is useful in order to gain insight on nm-scale electromagnetic fields. In the field of catalyst research electrostatic surface fields are of particular interest, since the potential drop over the surface can be assumed to play a major role in the reaction mechanisms.

Conventional off-axis holography reconstruction operates via the Fourier domain. As a consequence, the accessible range of spatial frequencies is band-limited by the carrier frequency of the hologram. A trade-off is always necessary in order to optimize fringe frequency, visibility, phase-contrast transfer and instrument stability for a certain range of spatial frequencies. In contrast, we demonstrate the implementation of phase-shifting holography at sub-nm resolution combined with an advanced drift correction scheme, and successfully match the results to multislice image simulations as well as conventional defocus series. The method is added to the in-situ capabilities of a third-order aberration-corrected environmental TEM in order to investigate surface effects in catalytic platinum samples under low pressures of oxygen and water.