Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 29: 2D Materials: Electronic Structure and Exitations II (joint session O/HL/TT)
TT 29.8: Vortrag
Mittwoch, 19. März 2025, 12:30–12:45, H11
Ultrafast lattice dynamics of monolayer ReS2 — •Victoria C. A. Taylor1, Yoav W. Windsor1,2, Samuel Lai3, Hyein Jung1,2, 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
Within the transition metal dichalcogenide (TMDC) material family, TMDCs containing rhenium stand out due to their low crystal symmetry. Instead of the common hexagonal structure, ReS2 exhibits in-plane 1D chains of rhenium ions due to a Peierls-like distortion. This highly anisotropic crystal structure results in a range of material properties, such as anisotropic effective carrier masses, polarization dependent optical absorption, and extremely weak interlayer coupling.
We present femtosecond electron diffraction (FED) measurements of monolayer ReS2. FED is a direct probe of photoexcited lattice dynamics, providing quantitative information on coherent and incoherent atomic vibrations on femtosecond timescales. In ReS2 monolayers we observe a strong and complex lattice response to photoexcitation. In particular, we observe a rapid (<1 ps) collective response, indicative of a concerted change in ionic positions within the unit cell. We measure the fluence dependence of this response and investigate the effect of the pronounced polarization dependence of the optical excitation, which results from the material’s in-plane anisotropy.
Keywords: ReS2; lattice dynamics; ultrafast; femtosecond electron diffraction; monolayer