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O: Fachverband Oberflächenphysik
O 71: 2D Materials: Electronic structure, excitations, etc. – Poster (joint session O/TT)
O 71.11: Poster
Mittwoch, 11. März 2026, 18:00–20:00, P2
Ultrafast Photocarrier-Induced Ionic Rearrangement in Monolayer ReS2 Probed with Femtosecond Electron Diffraction — •Victoria C. A. Taylor1, Yoav W. Windsor1,2, Samuel Lai3, Hyein Jung1,2, Martin Wolf1, Fang Lui3, and Ralph Ernstorfer1,2 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany — 2Technische Universität Berlin, 10623 Berlin, Germany — 3Stanford University, Stanford, CA 94305, USA
Rhenium disulphide (ReS2) exhibits a distorted crystal structure compared to prototypical hexagonal transition metal dichalcogenides. This Peierls-like distortion results in quasi-1D chains of Re ions running in plane through each layer of ReS2, which give rise to prominent anisotropic properties, such as polarization dependent optical absorption and anisotropic effective carrier masses.
We investigate the ultrafast lattice dynamics of monolayer ReS2 with femtosecond electron diffraction (FED). Leveraging the strength of FED as a direct and quantitative measurement of the crystal lattice, we fit the intensities of many hundreds of Bragg peaks at each time delay to extract time resolved crystallographic information.
With this method, we not only resolve the increase in the incoherent phonon population (Debye-Waller), but also reveal a concerted atomic rearrangement within the lattice, with the ions rapidly (< 1 ps) moving away from their equilibrium atomic coordinates and returning on timescales of a few picoseconds. We associate this response with the aforementioned distortion, and discuss the physical origin.
Keywords: ReS2; lattice dynamics; ultrafast; femtosecond electron diffraction; monolayer