Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 22: Surface dynamics – Poster

O 22.5: Poster

Montag, 9. März 2026, 18:00–20:00, P2

Atomic vibrations in the icosahedral quasicrystal AlPdMn studied with femtosecond electron diffraction — •Moritz Schlechtriem^{1, 2}, Victoria C. A. Taylor², Hyein Jung^{1, 2}, Ralph Ernstorfer^{1, 2}, and Yoav William Windsor^{1, 2} — ¹Technische Universität Berlin — ²Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

Quasicrystals (QCs) are materials in which the atomic arrangement lacks periodicity but exhibits perfect spatial order. QCs therefore produce sharp diffraction patterns with unconventional features such as 5-fold rotational symmetry. Due to the aperiodic nature of QCs, phonons are insufficient to fully describe atomic vibrations. Phasons are quasiparticles related to atomic motion in the presence of aperiodicity, and their group velocity can exceed the speed of sound. The resulting enhanced thermal conductivity gives rise to potential applications of QCs, e.g. in nanoelectronics.

Here we use pump-probe femtosecond electron diffraction (FED) to study ultrafast atomic vibrations in QCs. This enables us to study the femtosecond evolution of photoinduced atomic motion, shedding light on the coupling mechanisms between electrons, phonons and phasons.

In this presentation we focus on the icosahedral QC alloy AlPdMn. FED results, in which different high-symmetry directions (e.g. the 5-fold rotation axis) are probed, will be presented.

Keywords: quasicrystals; ultrafast phenomena; ultrafast electron diffraction; lattice dynamics